Online courses directory (237)

Videos exploring why algebra was developed and how it helps us explain our world. Origins of Algebra. Abstract-ness. The Beauty of Algebra. Descartes and Cartesian Coordinates. Why all the letters in Algebra?. What is a variable?. Why aren't we using the multiplication sign. Example: evaluating an expression. Example: evaluate a formula using substitution. Evaluating exponential expressions 2. Evaluating expressions in one variable. Expressions with two variables. Example: Evaluating expressions with 2 variables. Examples of evaluating variable expressions. Evaluating expressions in 2 variables. Example evaluating expressions in word problems. Evaluating expressions 3. Combining like terms. Adding like rational terms. Combining Like Terms 1. Combining Like Terms 2. Combining Like Terms 3. Combining like terms. Combining like terms and the distributive property. Combining like terms with distribution. Factoring a linear expression with rational terms. Distributive property with rational terms. Manipulating linear expressions with rational coefficients. Equivalent forms of expressions 1. Equivalent forms of expressions 1. Writing Expressions 1. Writing expressions. Writing Expressions 2. Writing expressions 2 exercise example. Writing expressions 2. Interpreting linear expressions example. Interpreting linear expressions example 2. Interpreting linear expressions. Writing expressions 3 exercise example 1. Writing expressions 3 exercise example 2. Writing expressions 3 exercise example 3. Writing expressions 3. Why we do the same thing to both sides: simple equations. Representing a relationship with a simple equation. One-Step Equation Intuition. One step equation intuition exercise intro. One step equation intuition. Adding and subtracting the same thing from both sides. Intuition why we divide both sides. Why we do the same thing to both sides: two-step equations. Why we do the same thing to both sides: multi-step equations. Why we do the same thing to both sides basic systems. Why all the letters in Algebra?. Super Yoga Plans- Basic Variables and Equations. Super Yoga Plans- Solving One-Step Equations. Constructing and solving equations in the real world 1. Super Yoga Plans- Plotting Points. Super Yoga Plans- Solving Systems by Substitution. Super Yoga Plans- Solving Systems by Elimination. Variables Expressions and Equations. Solving equations and inequalities through substitution example 1. Solving equations and inequalities through substitution example 2. Solving equations and inequalities through substitution example 3. Solving equations and inequalities through substitution example 4. Solving equations and inequalities through substitution. Dependent and independent variables exercise example 1. Dependent and independent variables exercise example 2. Dependent and independent variables exercise example 3. Dependent and independent variables. Origins of Algebra. Abstract-ness. The Beauty of Algebra. Descartes and Cartesian Coordinates. Why all the letters in Algebra?. What is a variable?. Why aren't we using the multiplication sign. Example: evaluating an expression. Example: evaluate a formula using substitution. Evaluating exponential expressions 2. Evaluating expressions in one variable. Expressions with two variables. Example: Evaluating expressions with 2 variables. Examples of evaluating variable expressions. Evaluating expressions in 2 variables. Example evaluating expressions in word problems. Evaluating expressions 3. Combining like terms. Adding like rational terms. Combining Like Terms 1. Combining Like Terms 2. Combining Like Terms 3. Combining like terms. Combining like terms and the distributive property. Combining like terms with distribution. Factoring a linear expression with rational terms. Distributive property with rational terms. Manipulating linear expressions with rational coefficients. Equivalent forms of expressions 1. Equivalent forms of expressions 1. Writing Expressions 1. Writing expressions. Writing Expressions 2. Writing expressions 2 exercise example. Writing expressions 2. Interpreting linear expressions example. Interpreting linear expressions example 2. Interpreting linear expressions. Writing expressions 3 exercise example 1. Writing expressions 3 exercise example 2. Writing expressions 3 exercise example 3. Writing expressions 3. Why we do the same thing to both sides: simple equations. Representing a relationship with a simple equation. One-Step Equation Intuition. One step equation intuition exercise intro. One step equation intuition. Adding and subtracting the same thing from both sides. Intuition why we divide both sides. Why we do the same thing to both sides: two-step equations. Why we do the same thing to both sides: multi-step equations. Why we do the same thing to both sides basic systems. Why all the letters in Algebra?. Super Yoga Plans- Basic Variables and Equations. Super Yoga Plans- Solving One-Step Equations. Constructing and solving equations in the real world 1. Super Yoga Plans- Plotting Points. Super Yoga Plans- Solving Systems by Substitution. Super Yoga Plans- Solving Systems by Elimination. Variables Expressions and Equations. Solving equations and inequalities through substitution example 1. Solving equations and inequalities through substitution example 2. Solving equations and inequalities through substitution example 3. Solving equations and inequalities through substitution example 4. Solving equations and inequalities through substitution. Dependent and independent variables exercise example 1. Dependent and independent variables exercise example 2. Dependent and independent variables exercise example 3. Dependent and independent variables.

Why we do the same thing to both sides: simple equations. Representing a relationship with a simple equation. One-Step Equation Intuition. One step equation intuition exercise intro. One step equation intuition. Adding and subtracting the same thing from both sides. Intuition why we divide both sides. Why we do the same thing to both sides: two-step equations. Why we do the same thing to both sides: multi-step equations. Why we do the same thing to both sides basic systems. Super Yoga Plans- Basic Variables and Equations. Super Yoga Plans- Solving One-Step Equations. Constructing and solving equations in the real world 1. Super Yoga Plans- Plotting Points. Super Yoga Plans- Solving Systems by Substitution. Super Yoga Plans- Solving Systems by Elimination. Constructing and solving equations in the real world 1 exercise. Simple Equations of the form Ax=B. Example solving x/3 =14. One-step equations with multiplication. Example solving x+5=54. Examples of one-step equations like Ax=B and x+A = B. One step equations. Solving Ax+B = C. Two-Step Equations. Example: Dimensions of a garden. Example: Two-step equation with x/4 term. 2-step equations. Basic linear equation word problem. Linear equation word problems. Linear equation word problem example. Linear equation word problems 2. Variables on both sides. Example 1: Variables on both sides. Example 2: Variables on both sides. Equation Special Cases. Equations with variables on both sides. Number of solutions to linear equations. Number of solutions to linear equations ex 2. Number of solutions to linear equations ex 3. Solutions to linear equations. Another Percent Word Problem. Percent word problems. Percent word problems 1 example 2). Solving Percent Problems 2. Solving Percent Problems 3. Percentage word problems 1. Percentage word problems 2. Rearrange formulas to isolate specific variables. Solving for a Variable. Solving for a Variable 2. Example: Solving for a variable. Solving equations in terms of a variable. Converting Repeating Decimals to Fractions 1. Converting 1-digit repeating decimals to fractions. Converting Repeating Decimals to Fractions 2. Converting multi-digit repeating decimals to fractions. Ex 1 Age word problem. Ex 2 Age word problem. Ex 3 Age word problem. Age word problems. Absolute Value Equations. Absolute Value Equations Example 1. Absolute Value Equation Example 2. Absolute Value Equations. Absolute Value Equations 1. Absolute value equation example. Absolute value equation with no solution. Absolute value equations. Absolute Value Inequalities. Absolute value inequalities Example 1. Absolute Inequalities 2. Absolute value inequalities example 3. Ex 2 Multi-step equation. Solving Equations with the Distributive Property. Solving equations with the distributive property 2. Ex 2: Distributive property to simplify . Ex 1: Distributive property to simplify . Ex 3: Distributive property to simplify . Multistep equations with distribution. Evaluating expressions where individual variable values are unknown. Evaluating expressions with unknown variables 2. Expressions with unknown variables. Expressions with unknown variables 2. Mixture problems 2. Basic Rate Problem. Early Train Word Problem. Patterns in Sequences 1. Patterns in Sequences 2. Equations of Sequence Patterns. Finding the 100th Term in a Sequence. Challenge example: Sum of integers. Integer sums. Integer sums. 2003 AIME II Problem 1. Bunch of examples. Mixture problems 3. Order of Operations examples. Algebra: Linear Equations 1. Algebra: Linear Equations 2. Algebra: Linear Equations 3. Algebra: Linear Equations 4. Averages. Taking percentages. Growing by a percentage. More percent problems. Age word problems 1. Age word problems 2. Age word problems 3. Why we do the same thing to both sides: simple equations. Representing a relationship with a simple equation. One-Step Equation Intuition. One step equation intuition exercise intro. One step equation intuition. Adding and subtracting the same thing from both sides. Intuition why we divide both sides. Why we do the same thing to both sides: two-step equations. Why we do the same thing to both sides: multi-step equations. Why we do the same thing to both sides basic systems. Super Yoga Plans- Basic Variables and Equations. Super Yoga Plans- Solving One-Step Equations. Constructing and solving equations in the real world 1. Super Yoga Plans- Plotting Points. Super Yoga Plans- Solving Systems by Substitution. Super Yoga Plans- Solving Systems by Elimination. Constructing and solving equations in the real world 1 exercise. Simple Equations of the form Ax=B. Example solving x/3 =14. One-step equations with multiplication. Example solving x+5=54. Examples of one-step equations like Ax=B and x+A = B. One step equations. Solving Ax+B = C. Two-Step Equations. Example: Dimensions of a garden. Example: Two-step equation with x/4 term. 2-step equations. Basic linear equation word problem. Linear equation word problems. Linear equation word problem example. Linear equation word problems 2. Variables on both sides. Example 1: Variables on both sides. Example 2: Variables on both sides. Equation Special Cases. Equations with variables on both sides. Number of solutions to linear equations. Number of solutions to linear equations ex 2. Number of solutions to linear equations ex 3. Solutions to linear equations. Another Percent Word Problem. Percent word problems. Percent word problems 1 example 2). Solving Percent Problems 2. Solving Percent Problems 3. Percentage word problems 1. Percentage word problems 2. Rearrange formulas to isolate specific variables. Solving for a Variable. Solving for a Variable 2. Example: Solving for a variable. Solving equations in terms of a variable. Converting Repeating Decimals to Fractions 1. Converting 1-digit repeating decimals to fractions. Converting Repeating Decimals to Fractions 2. Converting multi-digit repeating decimals to fractions. Ex 1 Age word problem. Ex 2 Age word problem. Ex 3 Age word problem. Age word problems. Absolute Value Equations. Absolute Value Equations Example 1. Absolute Value Equation Example 2. Absolute Value Equations. Absolute Value Equations 1. Absolute value equation example. Absolute value equation with no solution. Absolute value equations. Absolute Value Inequalities. Absolute value inequalities Example 1. Absolute Inequalities 2. Absolute value inequalities example 3. Ex 2 Multi-step equation. Solving Equations with the Distributive Property. Solving equations with the distributive property 2. Ex 2: Distributive property to simplify . Ex 1: Distributive property to simplify . Ex 3: Distributive property to simplify . Multistep equations with distribution. Evaluating expressions where individual variable values are unknown. Evaluating expressions with unknown variables 2. Expressions with unknown variables. Expressions with unknown variables 2. Mixture problems 2. Basic Rate Problem. Early Train Word Problem. Patterns in Sequences 1. Patterns in Sequences 2. Equations of Sequence Patterns. Finding the 100th Term in a Sequence. Challenge example: Sum of integers. Integer sums. Integer sums. 2003 AIME II Problem 1. Bunch of examples. Mixture problems 3. Order of Operations examples. Algebra: Linear Equations 1. Algebra: Linear Equations 2. Algebra: Linear Equations 3. Algebra: Linear Equations 4. Averages. Taking percentages. Growing by a percentage. More percent problems. Age word problems 1. Age word problems 2. Age word problems 3.

Exploring a world where both sides aren't equal anymore!. Inequalities Using Multiplication and Division. One-step inequality with multiplication and division example. Constructing and solving one-step inequality. One step inequalities. One-Step inequality involving addition. Inequalities Using Addition and Subtraction. Two-step inequality example. Multi-Step Inequalities. Multi-Step Inequalities 2. Multi-Step Inequalities 3. Multi-step linear inequalities. Interpreting Inequalities. Writing and using inequalities 2. Writing and using inequalities 3. Interpreting and solving linear inequalities. Inequality examples. Compound Inequalities. Compound Inequalities. Compound Inequalities 2. Compound Inequalities 3. Compound Inequalities 4. Compound inequalities. Absolute Value Inequalities. Absolute value inequalities Example 1. Absolute Value Inequalities Example 2. Absolute value inequalities example 3. Writing and using inequalities. Dogs cats and bears in a pet store visual argument. Dogs cats and bears in a pet store analytic argument. Reasoning through inequality expressions. Using expressions to understand relationships. Structure in expressions 1. Inequalities Using Multiplication and Division. One-step inequality with multiplication and division example. Constructing and solving one-step inequality. One step inequalities. One-Step inequality involving addition. Inequalities Using Addition and Subtraction. Two-step inequality example. Multi-Step Inequalities. Multi-Step Inequalities 2. Multi-Step Inequalities 3. Multi-step linear inequalities. Interpreting Inequalities. Writing and using inequalities 2. Writing and using inequalities 3. Interpreting and solving linear inequalities. Inequality examples. Compound Inequalities. Compound Inequalities. Compound Inequalities 2. Compound Inequalities 3. Compound Inequalities 4. Compound inequalities. Absolute Value Inequalities. Absolute value inequalities Example 1. Absolute Value Inequalities Example 2. Absolute value inequalities example 3. Writing and using inequalities. Dogs cats and bears in a pet store visual argument. Dogs cats and bears in a pet store analytic argument. Reasoning through inequality expressions. Using expressions to understand relationships. Structure in expressions 1.

Understanding and solving logarithms, including natural logs. Introduction to Logarithms. Logarithm of a Power. Sum of Logarithms with Same Base. Introduction to logarithm properties. Introduction to logarithm properties (part 2). Using Multiple Logarithm Properties to Simplify. Change of Base Formula. Logarithmic Scale. Richter Scale. Logarithmic Equations. Solving Logarithmic Equations. Proof: log a + log b = log ab. Proof: log_a (B) = (log_x (B))/(log_x (A)). Proof: A(log B) = log (B^A), log A - log B = log (A/B). Natural Logarithm with a Calculator. Calculator for Natural Logarithms. Graphing Natural Logarithm Function.

Logarithms. Ex: Converting an exponential to logarithmic statement. Evaluating logarithms. Fancier logarithm expressions. Evaluating logarithms 2. Graphing Logarithmic Functions. Introduction to Logarithms. Introduction to logarithm properties. Introduction to logarithm properties (part 2). Logarithm of a Power. Sum of Logarithms with Same Base. Using Multiple Logarithm Properties to Simplify. Operations with logarithms. Change of Base Formula. Proof: log a + log b = log ab. Proof: A(log B) = log (B^A), log A - log B = log (A/B). Change of base formula proof. Logarithmic Equations. Solving Logarithmic Equations. Solving Logarithmic Equations. Logarithmic Scale. Richter Scale. Natural Logarithm with a Calculator. Calculator for Natural Logarithms. Graphing Natural Logarithm Function. Logarithms. Ex: Converting an exponential to logarithmic statement. Evaluating logarithms. Fancier logarithm expressions. Evaluating logarithms 2. Graphing Logarithmic Functions. Introduction to Logarithms. Introduction to logarithm properties. Introduction to logarithm properties (part 2). Logarithm of a Power. Sum of Logarithms with Same Base. Using Multiple Logarithm Properties to Simplify. Operations with logarithms. Change of Base Formula. Proof: log a + log b = log ab. Proof: A(log B) = log (B^A), log A - log B = log (A/B). Change of base formula proof. Logarithmic Equations. Solving Logarithmic Equations. Solving Logarithmic Equations. Logarithmic Scale. Richter Scale. Natural Logarithm with a Calculator. Calculator for Natural Logarithms. Graphing Natural Logarithm Function.

Understanding and solving matrices. Introduction to the matrix. Matrix dimensions. Scalar multiplication. Scalar matrix multiplication. Matrix addition and subtraction. Matrix addition and subtraction. Transpose of a matrix. Matrix transpose. Multiplying a matrix by a column vector. Multiplying a matrix by a vector. Multiplying a matrix by a matrix. Multiplying a matrix by a matrix. Defined and undefined matrix operations. Defined and undefined matrix operations. Matrix multiplication (part 1). Matrix multiplication (part 2). Finding the Determinant of a 2x2 matrix. Determinant of a 2x2 matrix. Inverse of a 2x2 matrix. Idea Behind Inverting a 2x2 Matrix. Inverse of a 2x2 matrix. Matrices to solve a system of equations. Matrices to solve a vector combination problem. Finding the determinant of a 3x3 matrix method 1. Finding the determinant of a 3x3 matrix method 2. Determinant of a 3x3 matrix. Inverting 3x3 part 1: Calculating Matrix of Minors and Cofactor Matrix. Inverting 3x3 part 2: Determinant and Adjugate of a Matrix. Classic video on inverting a 3x3 matrix part 1. Classic video on inverting a 3x3 matrix part 2. Singular Matrices. Inverse of a 3x3 matrix. Matrices: Reduced Row Echelon Form 1. Matrices: Reduced Row Echelon Form 2. Matrices: Reduced Row Echelon Form 3. Introduction to the matrix. Matrix dimensions. Scalar multiplication. Scalar matrix multiplication. Matrix addition and subtraction. Matrix addition and subtraction. Transpose of a matrix. Matrix transpose. Multiplying a matrix by a column vector. Multiplying a matrix by a vector. Multiplying a matrix by a matrix. Multiplying a matrix by a matrix. Defined and undefined matrix operations. Defined and undefined matrix operations. Matrix multiplication (part 1). Matrix multiplication (part 2). Finding the Determinant of a 2x2 matrix. Determinant of a 2x2 matrix. Inverse of a 2x2 matrix. Idea Behind Inverting a 2x2 Matrix. Inverse of a 2x2 matrix. Matrices to solve a system of equations. Matrices to solve a vector combination problem. Finding the determinant of a 3x3 matrix method 1. Finding the determinant of a 3x3 matrix method 2. Determinant of a 3x3 matrix. Inverting 3x3 part 1: Calculating Matrix of Minors and Cofactor Matrix. Inverting 3x3 part 2: Determinant and Adjugate of a Matrix. Classic video on inverting a 3x3 matrix part 1. Classic video on inverting a 3x3 matrix part 2. Singular Matrices. Inverse of a 3x3 matrix. Matrices: Reduced Row Echelon Form 1. Matrices: Reduced Row Echelon Form 2. Matrices: Reduced Row Echelon Form 3.

This topic will add a ton of tools to your algebraic toolbox. You'll be able to multiply any expression and learn to factor a bunch a well. This will allow you to solve a broad array of problems in algebra. Factoring Special Products. Example 1: Factoring difference of squares. Factoring difference of squares 1. Example 2: Factoring difference of squares. Factoring difference of squares 2. Factoring to produce difference of squares. Factoring difference of squares 3. Example: Factoring perfect square trinomials. Example: Factoring a fourth degree expression. Example: Factoring special products. Multiplying Monomials. Dividing Monomials. Multiplying and Dividing Monomials 1. Multiplying and Dividing Monomials 2. Multiplying and Dividing Monomials 3. Monomial Greatest Common Factor. Multiplying binomials word problem. FOIL for multiplying binomials. Multiplying Binomials with Radicals. Multiplying binomials example 1. FOIL method for multiplying binomials example 2. Square a Binomial. Special Products of Binomials. Multiplying binomials to get difference of squares. Squaring a binomial. Multiplying expressions 0.5. Squaring a binomial example 2. Classic multiplying binomials video. Multiplying expressions 1. Factoring and the Distributive Property 3. Factoring linear binomials. Factoring linear binomials. Factoring and the Distributive Property. Factoring and the Distributive Property 2. Factor expressions using the GCF. Factoring quadratic expressions. Examples: Factoring simple quadratics. Example 1: Factoring quadratic expressions. Factoring polynomials 1. Example 1: Factoring trinomials with a common factor. Factoring polynomials 2. Factor by Grouping and Factoring Completely. Example: Basic grouping. Example 1: Factoring by grouping. Example 2: Factoring by grouping. Example 3: Factoring by grouping. Example 4: Factoring by grouping. Example 5: Factoring by grouping. Example 6: Factoring by grouping. Factoring polynomials by grouping. Factoring quadratics with two variables. Factoring quadratics with two variables example. Factoring polynomials with two variables. Terms coefficients and exponents in a polynomial. Interesting Polynomial Coefficient Problem. Polynomials1. Polynomials 2. Evaluating a polynomial at a given value. Simplify a polynomial. Adding Polynomials. Example: Adding polynomials with multiple variables. Addition and Subtraction of Polynomials. Adding and Subtracting Polynomials 1. Adding and Subtracting Polynomials 2. Adding and Subtracting Polynomials 3. Subtracting Polynomials. Subtracting polynomials with multiple variables. Adding and subtracting polynomials. Multiplying Monomials by Polynomials. Multiplying Polynomials. Multiplying Polynomials 3. More multiplying polynomials. Multiplying polynomials. Polynomial Division. Polynomial divided by monomial. Dividing multivariable polynomial with monomial. Dividing polynomials 1. Dividing polynomials with remainders. Synthetic Division. Synthetic Division Example 2. Why Synthetic Division Works. Factoring Sum of Cubes. Difference of Cubes Factoring. Algebraic Long Division. Algebra II: Simplifying Polynomials. Factoring Special Products. Example 1: Factoring difference of squares. Factoring difference of squares 1. Example 2: Factoring difference of squares. Factoring difference of squares 2. Factoring to produce difference of squares. Factoring difference of squares 3. Example: Factoring perfect square trinomials. Example: Factoring a fourth degree expression. Example: Factoring special products. Multiplying Monomials. Dividing Monomials. Multiplying and Dividing Monomials 1. Multiplying and Dividing Monomials 2. Multiplying and Dividing Monomials 3. Monomial Greatest Common Factor. Multiplying binomials word problem. FOIL for multiplying binomials. Multiplying Binomials with Radicals. Multiplying binomials example 1. FOIL method for multiplying binomials example 2. Square a Binomial. Special Products of Binomials. Multiplying binomials to get difference of squares. Squaring a binomial. Multiplying expressions 0.5. Squaring a binomial example 2. Classic multiplying binomials video. Multiplying expressions 1. Factoring and the Distributive Property 3. Factoring linear binomials. Factoring linear binomials. Factoring and the Distributive Property. Factoring and the Distributive Property 2. Factor expressions using the GCF. Factoring quadratic expressions. Examples: Factoring simple quadratics. Example 1: Factoring quadratic expressions. Factoring polynomials 1. Example 1: Factoring trinomials with a common factor. Factoring polynomials 2. Factor by Grouping and Factoring Completely. Example: Basic grouping. Example 1: Factoring by grouping. Example 2: Factoring by grouping. Example 3: Factoring by grouping. Example 4: Factoring by grouping. Example 5: Factoring by grouping. Example 6: Factoring by grouping. Factoring polynomials by grouping. Factoring quadratics with two variables. Factoring quadratics with two variables example. Factoring polynomials with two variables. Terms coefficients and exponents in a polynomial. Interesting Polynomial Coefficient Problem. Polynomials1. Polynomials 2. Evaluating a polynomial at a given value. Simplify a polynomial. Adding Polynomials. Example: Adding polynomials with multiple variables. Addition and Subtraction of Polynomials. Adding and Subtracting Polynomials 1. Adding and Subtracting Polynomials 2. Adding and Subtracting Polynomials 3. Subtracting Polynomials. Subtracting polynomials with multiple variables. Adding and subtracting polynomials. Multiplying Monomials by Polynomials. Multiplying Polynomials. Multiplying Polynomials 3. More multiplying polynomials. Multiplying polynomials. Polynomial Division. Polynomial divided by monomial. Dividing multivariable polynomial with monomial. Dividing polynomials 1. Dividing polynomials with remainders. Synthetic Division. Synthetic Division Example 2. Why Synthetic Division Works. Factoring Sum of Cubes. Difference of Cubes Factoring. Algebraic Long Division. Algebra II: Simplifying Polynomials.

Using polynomial expressions and factoring polynomials. Terms coefficients and exponents in a polynomial. Interesting Polynomial Coefficient Problem. Polynomials1. Polynomials 2. Evaluating a polynomial at a given value. Simplify a polynomial. Adding Polynomials. Example: Adding polynomials with multiple variables. Addition and Subtraction of Polynomials. Adding and Subtracting Polynomials 1. Adding and Subtracting Polynomials 2. Adding and Subtracting Polynomials 3. Subtracting Polynomials. Subtracting polynomials with multiple variables. Adding and subtracting polynomials. Multiplying Monomials. Dividing Monomials. Multiplying and Dividing Monomials 1. Multiplying and Dividing Monomials 2. Multiplying and Dividing Monomials 3. Monomial Greatest Common Factor. Factoring and the Distributive Property. Factoring and the Distributive Property 2. Factoring and the Distributive Property 3. Multiplying Binomials with Radicals. Multiplication of Polynomials. Multiplying Binomials. Multiplying Polynomials1. Multiplying Polynomials 2. Square a Binomial. Special Products of Binomials. Special Polynomials Products 1. Factor polynomials using the GCF. Special Products of Polynomials 1. Special Products of Polynomials 2. Multiplying expressions 0.5. Factoring linear binomials. Multiplying expressions 1. Multiplying Monomials by Polynomials. Multiplying Polynomials. Multiplying Polynomials 3. More multiplying polynomials. Multiplying polynomials. Level 1 multiplying expressions. Polynomial Division. Polynomial divided by monomial. Dividing multivariable polynomial with monomial. Dividing polynomials 1. Dividing polynomials with remainders. Synthetic Division. Synthetic Division Example 2. Why Synthetic Division Works. Factoring Sum of Cubes. Difference of Cubes Factoring. Algebraic Long Division. Algebra II: Simplifying Polynomials. Terms coefficients and exponents in a polynomial. Interesting Polynomial Coefficient Problem. Polynomials1. Polynomials 2. Evaluating a polynomial at a given value. Simplify a polynomial. Adding Polynomials. Example: Adding polynomials with multiple variables. Addition and Subtraction of Polynomials. Adding and Subtracting Polynomials 1. Adding and Subtracting Polynomials 2. Adding and Subtracting Polynomials 3. Subtracting Polynomials. Subtracting polynomials with multiple variables. Adding and subtracting polynomials. Multiplying Monomials. Dividing Monomials. Multiplying and Dividing Monomials 1. Multiplying and Dividing Monomials 2. Multiplying and Dividing Monomials 3. Monomial Greatest Common Factor. Factoring and the Distributive Property. Factoring and the Distributive Property 2. Factoring and the Distributive Property 3. Multiplying Binomials with Radicals. Multiplication of Polynomials. Multiplying Binomials. Multiplying Polynomials1. Multiplying Polynomials 2. Square a Binomial. Special Products of Binomials. Special Polynomials Products 1. Factor polynomials using the GCF. Special Products of Polynomials 1. Special Products of Polynomials 2. Multiplying expressions 0.5. Factoring linear binomials. Multiplying expressions 1. Multiplying Monomials by Polynomials. Multiplying Polynomials. Multiplying Polynomials 3. More multiplying polynomials. Multiplying polynomials. Level 1 multiplying expressions. Polynomial Division. Polynomial divided by monomial. Dividing multivariable polynomial with monomial. Dividing polynomials 1. Dividing polynomials with remainders. Synthetic Division. Synthetic Division Example 2. Why Synthetic Division Works. Factoring Sum of Cubes. Difference of Cubes Factoring. Algebraic Long Division. Algebra II: Simplifying Polynomials.

Solving quadratics through factoring, completing the square, graphing, and the quadratic equation. Factoring Quadratic Expressions. Solving Quadratic Equations by Square Roots. Completing the square. Graphing a Quadratic Function. Graphs of Quadratic Functions. Quadratic Functions 3. Quadratic Equations in Standard Form. Quadratic Formula 1. Proof of Quadratic Formula. Complex Roots from the Quadratic Formula. Discriminant for Types of Solutions for a Quadratic. Solving Quadratic Equations by Factoring. Solving Quadratic Equations by Factoring 2. Solving Quadratic Equations by Factoring 3. CA Algebra I: Factoring Quadratics. Solving a quadratic by factoring. Applications Problem Factoring Quadratics. Algebra II: Quadratics and Shifts. Algebra II: Shifting Quadratic Graphs. Completing the Square 1. Completing the Square 3. Completing the Square 2. Completing the Square 4. Completing the Square to Solve Quadratic Equations. CA Algebra I: Completing the Square. Solving Quadratic Equations by Completing the Square. Completing Perfect Square Trinomials. Introduction to the quadratic equation. Quadratic Equation part 2. Quadratic Formula 2. Quadratic Formula 3. CA Algebra I: Quadratic Equation. CA Algebra I: Quadratic Roots. Simple Quadratic Equation. Applying the Quadratic Formula. Application Problem with Quadratic Formula. Discriminant of Quadratic Equations. Quadratic Formula (proof).

In this topic, we'll analyze, graph and solve quadratic equations. Example 1: Solving a quadratic equation by factoring. Example 2: Solving a quadratic equation by factoring. Example 3: Solving a quadratic equation by factoring. Example 4: Solving a quadratic equation by factoring. Solving quadratics by factoring. Solving quadratics by factoring 2. Solving Quadratic Equations by Square Roots. Example: Solving simple quadratic. Solving quadratics by taking the square root. Solving Quadratic Equations by Completing the Square. Completing the square (old school). Example: Completing perfect square trinomials. Example 1: Completing the square. Example 2: Completing the square. Example 3: Completing the square. Example 4: Completing the square. Example 5: Completing the square. Completing the square 1. Completing the square 2. How to use the Quadratic Formula. Example: Quadratics in standard form. Proof of Quadratic Formula. Example 1: Using the quadratic formula. Example 2: Using the quadratic formula. Example 3: Using the quadratic formula. Example 4: Applying the quadratic formula. Example 5: Using the quadratic formula. Quadratic formula. Example: Complex roots for a quadratic. Quadratic formula with complex solutions. Discriminant of Quadratic Equations. Discriminant for Types of Solutions for a Quadratic. Solutions to quadratic equations. Graphing a parabola with a table of values. Parabola vertex and axis of symmetry. Graphing a parabola by finding the roots and vertex. Finding the vertex of a parabola example. Vertex of a parabola. Multiple examples graphing parabolas using roots and vertices. Graphing a parabola using roots and vertex. Graphing parabolas in standard form. Graphing a parabola in vertex form. Graphing parabolas in vertex form. Graphing parabolas in all forms. Parabola Focus and Directrix 1. Focus and Directrix of a Parabola 2. Using the focus and directrix to find the equation of a parabola. Parabola intuition 3. Quadratic Inequalities. Quadratic Inequalities (Visual Explanation). Solving a quadratic by factoring. CA Algebra I: Factoring Quadratics. Algebra II: Quadratics and Shifts. Examples: Graphing and interpreting quadratics. CA Algebra I: Completing the Square. Introduction to the quadratic equation. Quadratic Equation part 2. Quadratic Formula (proof). CA Algebra I: Quadratic Equation. CA Algebra I: Quadratic Roots. Example 1: Solving a quadratic equation by factoring. Example 2: Solving a quadratic equation by factoring. Example 3: Solving a quadratic equation by factoring. Example 4: Solving a quadratic equation by factoring. Solving quadratics by factoring. Solving quadratics by factoring 2. Solving Quadratic Equations by Square Roots. Example: Solving simple quadratic. Solving quadratics by taking the square root. Solving Quadratic Equations by Completing the Square. Completing the square (old school). Example: Completing perfect square trinomials. Example 1: Completing the square. Example 2: Completing the square. Example 3: Completing the square. Example 4: Completing the square. Example 5: Completing the square. Completing the square 1. Completing the square 2. How to use the Quadratic Formula. Example: Quadratics in standard form. Proof of Quadratic Formula. Example 1: Using the quadratic formula. Example 2: Using the quadratic formula. Example 3: Using the quadratic formula. Example 4: Applying the quadratic formula. Example 5: Using the quadratic formula. Quadratic formula. Example: Complex roots for a quadratic. Quadratic formula with complex solutions. Discriminant of Quadratic Equations. Discriminant for Types of Solutions for a Quadratic. Solutions to quadratic equations. Graphing a parabola with a table of values. Parabola vertex and axis of symmetry. Graphing a parabola by finding the roots and vertex. Finding the vertex of a parabola example. Vertex of a parabola. Multiple examples graphing parabolas using roots and vertices. Graphing a parabola using roots and vertex. Graphing parabolas in standard form. Graphing a parabola in vertex form. Graphing parabolas in vertex form. Graphing parabolas in all forms. Parabola Focus and Directrix 1. Focus and Directrix of a Parabola 2. Using the focus and directrix to find the equation of a parabola. Parabola intuition 3. Quadratic Inequalities. Quadratic Inequalities (Visual Explanation). Solving a quadratic by factoring. CA Algebra I: Factoring Quadratics. Algebra II: Quadratics and Shifts. Examples: Graphing and interpreting quadratics. CA Algebra I: Completing the Square. Introduction to the quadratic equation. Quadratic Equation part 2. Quadratic Formula (proof). CA Algebra I: Quadratic Equation. CA Algebra I: Quadratic Roots.

You have probably been wondering whether our powers of algebraic problem solving break down if we divide by the variable or we have entire expressions in denominator of a fraction. Well, they don't! In this topic, you'll learn how to interpret and manipulate rational expressions (when you have one algebraic expression divided by another)!. Simplifying Rational Expressions Introduction. Simplifying Rational Expressions 1. Dividing polynomials by binomials 1. Simplifying Rational Expressions 2. Dividing polynomials by binomials 2. Simplifying rational expressions 2. Simplifying Rational Expressions 3. Simplifying Rational Expressions Example 2. Dividing polynomials by binomials 3. Simplifying rational expressions 3. Simplifying rational expressions 4. Adding and Subtracting Rational Expressions. Adding and Subtracting Rational Expressions 2. Adding and Subtracting Rational Expressions 3. Subtracting Rational Expressions. Simplifying First for Subtracting Rational Expressions. Adding and subtracting rational expressions 0.5. Adding and subtracting rational expressions 1. Adding and subtracting rational expressions 1.5. Adding and subtracting rational expressions 2. Adding and subtracting rational expressions 3. Multiplying and Simplifying Rational Expressions. Multiplying and Dividing Rational Expressions 1. Multiplying and Dividing Rational Expressions 2. Multiplying and Dividing Rational Expressions 3. Multiplying and dividing rational expressions 1. Multiplying and dividing rational expressions 2. Multiplying and dividing rational expressions 3. Multiplying and dividing rational expressions 4. Multiplying and dividing rational expressions 5. Rationalizing Denominators of Expressions. Asymptotes of Rational Functions. Another Rational Function Graph Example. A Third Example of Graphing a Rational Function. Partial Fraction Expansion 1. Partial Fraction Expansion 2. Partial Fraction Expansion 3. Partial fraction expansion. Ex 1 Multi step equation. Solving rational equations 1. Rational Equations. Solving Rational Equations 1. Solving Rational Equations 2. Solving Rational Equations 3. Applying Rational Equations 1. Applying Rational Equations 2. Applying Rational Equations 3. Solving rational equations 2. Extraneous Solutions to Rational Equations. Extraneous solutions. Rational Inequalities. Rational Inequalities 2. Simplifying Rational Expressions Introduction. Simplifying Rational Expressions 1. Dividing polynomials by binomials 1. Simplifying Rational Expressions 2. Dividing polynomials by binomials 2. Simplifying rational expressions 2. Simplifying Rational Expressions 3. Simplifying Rational Expressions Example 2. Dividing polynomials by binomials 3. Simplifying rational expressions 3. Simplifying rational expressions 4. Adding and Subtracting Rational Expressions. Adding and Subtracting Rational Expressions 2. Adding and Subtracting Rational Expressions 3. Subtracting Rational Expressions. Simplifying First for Subtracting Rational Expressions. Adding and subtracting rational expressions 0.5. Adding and subtracting rational expressions 1. Adding and subtracting rational expressions 1.5. Adding and subtracting rational expressions 2. Adding and subtracting rational expressions 3. Multiplying and Simplifying Rational Expressions. Multiplying and Dividing Rational Expressions 1. Multiplying and Dividing Rational Expressions 2. Multiplying and Dividing Rational Expressions 3. Multiplying and dividing rational expressions 1. Multiplying and dividing rational expressions 2. Multiplying and dividing rational expressions 3. Multiplying and dividing rational expressions 4. Multiplying and dividing rational expressions 5. Rationalizing Denominators of Expressions. Asymptotes of Rational Functions. Another Rational Function Graph Example. A Third Example of Graphing a Rational Function. Partial Fraction Expansion 1. Partial Fraction Expansion 2. Partial Fraction Expansion 3. Partial fraction expansion. Ex 1 Multi step equation. Solving rational equations 1. Rational Equations. Solving Rational Equations 1. Solving Rational Equations 2. Solving Rational Equations 3. Applying Rational Equations 1. Applying Rational Equations 2. Applying Rational Equations 3. Solving rational equations 2. Extraneous Solutions to Rational Equations. Extraneous solutions. Rational Inequalities. Rational Inequalities 2.

Solving and writing algebraic ratios and proportions. Solving rational equations. Introduction to Ratios (new HD version). Understanding Proportions. Ratios as Fractions in Simplest Form. Simplifying Rates and Ratios. Find an Unknown in a Proportion. Ratio and Proportion. Find an Unknown in a Proportion 2. Another Take on the Rate Problem. Finding Unit Rates. Finding Unit Prices. Writing Proportions. Ratio problem with basic algebra (new HD). More advanced ratio problem--with Algebra (HD version). Alternate Solution to Ratio Problem (HD Version). Advanced ratio problems. Unit conversion. Conversion between metric units. Converting within the metric system. Converting pounds to ounces. Converting Gallons to quarts pints and cups. Converting Farenheit to Celsius. Comparing Celsius and Farenheit temperature scales. Applying the Metric System. U.S. Customary and Metric units. Converting Yards into Inches. Unit Conversion with Fractions. Performing arithmetic calculations on units of volume. Application problems involving units of weight. Solving application problems involving units of volume. Unit Conversion Example: Drug Dosage. Perimeter and Unit Conversion. Rational Equations. Solving Rational Equations 1. Solving Rational Equations 2. Solving Rational Equations 3. Applying Rational Equations 1. Applying Rational Equations 2. Applying Rational Equations 3. Extraneous Solutions to Rational Equations. Rational Inequalities 2.

What ratios and proportions are. Using them to solve problems in the real world. Ratio problem with basic algebra (new HD). Writing proportions. Writing proportions. Find an Unknown in a Proportion. Find an Unknown in a Proportion 2. Proportions 1. Proportions 2 exercise examples. Proportions 2. Constructing proportions to solve application problems. Constructing proportions to solve application problems. The Golden Ratio. Advanced ratio problems. More advanced ratio problem--with Algebra (HD version). Another Take on the Rate Problem. Alternate Solution to Ratio Problem (HD Version). Mountain height word problem. Ratio problem with basic algebra (new HD). Writing proportions. Writing proportions. Find an Unknown in a Proportion. Find an Unknown in a Proportion 2. Proportions 1. Proportions 2 exercise examples. Proportions 2. Constructing proportions to solve application problems. Constructing proportions to solve application problems. The Golden Ratio. Advanced ratio problems. More advanced ratio problem--with Algebra (HD version). Another Take on the Rate Problem. Alternate Solution to Ratio Problem (HD Version). Mountain height word problem.

Solving a system of equations or inequalities in two variables by elimination, substitution, and graphing. Trolls, Tolls, and Systems of Equations. Solving the Troll Riddle Visually. Solving Systems Graphically. Graphing systems of equations. King's Cupcakes: Solving Systems by Elimination. How many bags of potato chips do people eat?. Simple Elimination Practice. Systems of equations with simple elimination. Systems with Elimination Practice. Systems of equations with elimination. Talking bird solves systems with substitution. Practice using substitution for systems. Systems of equations with substitution. Systems of equations. Systems of equations word problems. Solving linear systems by graphing. Graphing systems of equations. Solving linear systems by substitution. Systems of equations with substitution. Solving systems of equations by elimination. Systems of equations with simple elimination. Solving systems of equations by multiplication. Systems of equations with elimination. Systems of equations. Special types of linear systems. Solutions to systems of equations. Old video on systems of equations. Solving linear systems by graphing. Testing a solution for a system of equations. Graphing Systems of Equations. Graphical Systems Application Problem. Example 2: Graphically Solving Systems. Example 3: Graphically Solving Systems. Solving Systems Graphically. Graphing systems of equations. Inconsistent systems of equations. Infinite solutions to systems. Consistent and Inconsistent Systems. Independent and Dependent Systems. Practice thinking about number of solutions to systems. Graphical solutions to systems. Solutions to systems of equations. Constructing solutions to systems of equations. Constructing consistent and inconsistent systems. Example 1: Solving systems by substitution. Example 2: Solving systems by substitution. Example 3: Solving systems by substitution. The Substitution Method. Substitution Method 2. Substitution Method 3. Practice using substitution for systems. Systems of equations with substitution. Example 1: Solving systems by elimination. Example 2: Solving systems by elimination. Addition Elimination Method 1. Addition Elimination Method 2. Addition Elimination Method 3. Addition Elimination Method 4. Example 3: Solving systems by elimination. Simple Elimination Practice. Systems of equations with simple elimination. Systems with Elimination Practice. Systems of equations with elimination. Using a system of equations to find the price of apples and oranges. Linear systems word problem with substitution. Systems of equations word problems. Systems of equation to realize you are getting ripped off. Thinking about multiple solutions to a system of equations. Understanding systems of equations word problems. Systems and rate problems. Systems and rate problems 2. Systems and rate problems 3. Officer on Horseback. Two Passing Bicycles Word Problem. Passed Bike Word Problem. System of equations for passing trains problem. Overtaking Word Problem. Multple examples of multiple constraint problems. Testing Solutions for a System of Inequalities. Visualizing the solution set for a system of inequalities. Graphing systems of inequalities. Graphing systems of inequalities 2. Graphing systems of inequalities. Graphing and solving systems of inequalities. System of Inequalities Application. CA Algebra I: Systems of Inequalities. Systems of Three Variables. Systems of Three Variables 2. Solutions to Three Variable System. Solutions to Three Variable System 2. Three Equation Application Problem. Non-Linear Systems of Equations 3. Non-Linear Systems of Equations 1. Non-Linear Systems of Equations 2. Non-Linear Systems of Equations 3. Systems of nonlinear equations 1. Systems of nonlinear equations 2. Systems of nonlinear equations 3. Systems of nonlinear equations. Trolls, Tolls, and Systems of Equations. Solving the Troll Riddle Visually. Solving Systems Graphically. Graphing systems of equations. King's Cupcakes: Solving Systems by Elimination. How many bags of potato chips do people eat?. Simple Elimination Practice. Systems of equations with simple elimination. Systems with Elimination Practice. Systems of equations with elimination. Talking bird solves systems with substitution. Practice using substitution for systems. Systems of equations with substitution. Systems of equations. Systems of equations word problems. Solving linear systems by graphing. Graphing systems of equations. Solving linear systems by substitution. Systems of equations with substitution. Solving systems of equations by elimination. Systems of equations with simple elimination. Solving systems of equations by multiplication. Systems of equations with elimination. Systems of equations. Special types of linear systems. Solutions to systems of equations. Old video on systems of equations. Solving linear systems by graphing. Testing a solution for a system of equations. Graphing Systems of Equations. Graphical Systems Application Problem. Example 2: Graphically Solving Systems. Example 3: Graphically Solving Systems. Solving Systems Graphically. Graphing systems of equations. Inconsistent systems of equations. Infinite solutions to systems. Consistent and Inconsistent Systems. Independent and Dependent Systems. Practice thinking about number of solutions to systems. Graphical solutions to systems. Solutions to systems of equations. Constructing solutions to systems of equations. Constructing consistent and inconsistent systems. Example 1: Solving systems by substitution. Example 2: Solving systems by substitution. Example 3: Solving systems by substitution. The Substitution Method. Substitution Method 2. Substitution Method 3. Practice using substitution for systems. Systems of equations with substitution. Example 1: Solving systems by elimination. Example 2: Solving systems by elimination. Addition Elimination Method 1. Addition Elimination Method 2. Addition Elimination Method 3. Addition Elimination Method 4. Example 3: Solving systems by elimination. Simple Elimination Practice. Systems of equations with simple elimination. Systems with Elimination Practice. Systems of equations with elimination. Using a system of equations to find the price of apples and oranges. Linear systems word problem with substitution. Systems of equations word problems. Systems of equation to realize you are getting ripped off. Thinking about multiple solutions to a system of equations. Understanding systems of equations word problems. Systems and rate problems. Systems and rate problems 2. Systems and rate problems 3. Officer on Horseback. Two Passing Bicycles Word Problem. Passed Bike Word Problem. System of equations for passing trains problem. Overtaking Word Problem. Multple examples of multiple constraint problems. Testing Solutions for a System of Inequalities. Visualizing the solution set for a system of inequalities. Graphing systems of inequalities. Graphing systems of inequalities 2. Graphing systems of inequalities. Graphing and solving systems of inequalities. System of Inequalities Application. CA Algebra I: Systems of Inequalities. Systems of Three Variables. Systems of Three Variables 2. Solutions to Three Variable System. Solutions to Three Variable System 2. Three Equation Application Problem. Non-Linear Systems of Equations 3. Non-Linear Systems of Equations 1. Non-Linear Systems of Equations 2. Non-Linear Systems of Equations 3. Systems of nonlinear equations 1. Systems of nonlinear equations 2. Systems of nonlinear equations 3. Systems of nonlinear equations.

Build your earth science vocabulary and learn about cycles of matter and types of sedimentary rocks through the Education Portal course Earth Science 101: Earth Science. Our series of video lessons and accompanying self-assessment quizzes can help you boost your scientific knowledge ahead of the Excelsior Earth Science exam . This course was designed by experienced educators and examines both science basics, like experimental design and systems of measurement, and more advanced topics, such as analysis of rock deformation and theories of continental drift.

Solve problems using Mathematics, Computer Science and more!. Introduction. The Discovery. Clue #1. Clue #2. Clue #3. Crypto Checkpoint 1. Clue #4. Checkpoint. Crypto Checkpoint 2. Crypto Checkpoint 3. What's Next?. Introduction. The Discovery. Clue #1. Clue #2. Clue #3. Crypto Checkpoint 1. Clue #4. Checkpoint. Crypto Checkpoint 2. Crypto Checkpoint 3. What's Next?.

The math behind human, animal and machine communication. What is Information Theory?. Prehistory: Proto-writing. Ptolemaic: Rosetta Stone. Ancient History: The Alphabet. Source Encoding. Visual Telegraphs (case study).

We've always been communicating.... as we moved from signal fires, to alphabets & electricity the problems remained the same. What is Information Theory?. Prehistory: Proto-writing. Ptolemaic: Rosetta Stone. Ancient History: The Alphabet. Source Encoding. Visual Telegraphs (case study). Decision Tree Exploration. Electrostatic Telegraphs (case study). The Battery & Electromagnetism. Morse Code & The Information Age. Morse code Exploration. What's Next?. Symbol Rate. Symbol Rate Exploration. Introduction to Channel Capacity. Message Space Exploration. Measuring Information. Galton Board Exploration. Origin of Markov Chains. Markov Chain Exploration. A Mathematical Theory of Communication. Markov Text Exploration. What's Next?. What is Information Theory?. Prehistory: Proto-writing. Ptolemaic: Rosetta Stone. Ancient History: The Alphabet. Source Encoding. Visual Telegraphs (case study). Decision Tree Exploration. Electrostatic Telegraphs (case study). The Battery & Electromagnetism. Morse Code & The Information Age. Morse code Exploration. What's Next?. Symbol Rate. Symbol Rate Exploration. Introduction to Channel Capacity. Message Space Exploration. Measuring Information. Galton Board Exploration. Origin of Markov Chains. Markov Chain Exploration. A Mathematical Theory of Communication. Markov Text Exploration. What's Next?.

20th century solutions to new problems in Cryptography. The Fundamental Theorem of Arithmetic. Public Key Cryptography: what is it?. The Discrete Logarithm Problem. Diffie-Hellman Key Exchange. RSA Encryption: step 1. RSA Encryption: step 2. RSA Encryption: step 3. Euler's Totient Function. RSA Encryption: step 4. What should we learn next?.

Adding and subtracting positive and negative whole numbers. Starts with 1+1=2 and covers carrying, borrowing, and word problems. Basic Addition. 1-digit addition. Basic Subtraction. 1-digit subtraction. Example: Adding two digit numbers (no carrying). 2-digit addition. Subtraction 2. Example: 2-digit subtraction (no borrowing). 2 and 3-digit subtraction. Level 2 Addition. Introduction to carrying when adding. Addition 3. Addition with carrying. Addition 4. 4-digit addition with carrying. Subtraction 3: Introduction to Borrowing or Regrouping. Why borrowing works. Borrowing once example 1. Borrowing once example 2. Subtraction with borrowing. Regrouping (borrowing) twice example. 4-digit subtraction with borrowing. Alternate mental subtraction method. Level 4 Subtraction. Subtraction Word Problem. Addition and subtraction word problems. Basic Addition. 1-digit addition. Basic Subtraction. 1-digit subtraction. Example: Adding two digit numbers (no carrying). 2-digit addition. Subtraction 2. Example: 2-digit subtraction (no borrowing). 2 and 3-digit subtraction. Level 2 Addition. Introduction to carrying when adding. Addition 3. Addition with carrying. Addition 4. 4-digit addition with carrying. Subtraction 3: Introduction to Borrowing or Regrouping. Why borrowing works. Borrowing once example 1. Borrowing once example 2. Subtraction with borrowing. Regrouping (borrowing) twice example. 4-digit subtraction with borrowing. Alternate mental subtraction method. Level 4 Subtraction. Subtraction Word Problem. Addition and subtraction word problems.