# Algebra foundations

## Overview and history of algebra

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Origins of algebraAbstract-nessThe beauty of algebraIntro to the coordinate planeWhy all the letters in algebra?

## Introduction to variables

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What is a variable?Why aren't we using the multiplication sign?Evaluating an expression with one variableEvaluating expressions with one variable
Practice
Evaluating expressions with one variableGet 5 of 7 questions to level up!

## Substitution and evaluating expressions

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Evaluating expressions with two variablesEvaluating expressions with two variablesEvaluating expressions with two variables: fractions & decimalsEvaluating expressions with two variables: fractions & decimals

## Combining like terms

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Intro to combining like termsSimplifying expressionsCombining like terms challenge problemSimplifying expressions with rational numbers
Practice
Combining like terms with negative coefficientsGet 5 of 7 questions to level up!
Combining like terms with rational coefficientsGet 3 of 4 questions to level up!

## Introduction to equivalent expressions

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Equivalent expressions
Practice
Equivalent expressionsGet 5 of 7 questions to level up!

## Division by zero

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Why dividing by zero is undefinedThe problem with dividing zero by zeroUndefined & indeterminate expressions