Introduction to algebra

This course is a part of Algebra (all content), a 20-course Topic series from Khan Academy.

This topic covers: - Evaluating algebraic expressions - Manipulating algebraic expressions & equivalent expressions - Seeing structure in expressions - Irrational numbers - Division by zero

This course contains 14 segments:

Overview and history of algebra

Did you realize that the word "algebra" comes from Arabic (just like "algorithm" and "al jazeera" and "Aladdin")? And what is so great about algebra anyway? This tutorial doesn't explore algebra so much as it introduces the history and ideas that underpin it.

Introduction to variables

Wait, why are we using letters in math? How can an 'x' represent a number? What number is it? This tutorial is great if you're just beginning to delve into the world of variables and expressions.

Substitution and evaluating expressions

Learn how to substitute (or "plug in") values for variables and evaluate algebraic expressions.

Evaluating expressions word problems

Learn how to plug in values to evaluate real-world expressions.

Writing algebraic expressions introduction

Learn the basics of writing expressions with variables.

Introduction to equivalent algebraic expressions

Learn to tell whether or not two algebraic expressions are equivalent by combining like terms and using the distributive property.

Dependent & independent variables

Sometimes one variable depends on another. For example, the amount of money you make might depend on how many hours you work.

Combining like terms

Learn how to combine like terms (with negative numbers and variables), including more complex problems involving the distributive property.

Interpreting linear expressions

Any expression (mathematical or otherwise) has meaning. Help us match the linear expression to the meaning options given. In some cases, more than one meaning may apply.

Irrational numbers

Learn what irrational numbers are. Also learn how to classify numbers as whole, integer, rational, and irrational.

Sums and products of rational and irrational numbers

Determine whether various combinations of rational and irrational numbers are rational or irrational themselves.

Proofs concerning irrational numbers

Learn some proofs about the existence of irrational numbers.

Division by zero

Sal uses algebraic reasoning to tackle the problems of dividing by zero.

Binary and hexadecimal number systems

Most of us are used to using the digits 0-9 to represent numbers in the base-10 (decimal)number system. In this tutorial, we'll see that is just one of many (really infinite) number systems. In particular, we will focus on the binary (base-2) and hexadecimal (base-16) systems.