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Free math lessons with worked examples, plus practice problems with full answers. Pick a course below or search for any topic.

A line with slope 2/3 Line through (2, 2) and (5, 4) on a coordinate grid. A dashed triangle shows a run of 3 and a rise of 2, so the slope is 2/3. 2 4 6 8 2 4 6 x y (2, 2) (5, 4) run = 3 rise = 2 slope = 2/3

Courses

Start with the course you’re taking. Each course index lists every lesson in the order it’s usually taught.

Fraction bar with 3 of 4 parts shaded

Pre-Algebra (Math Basics)

Integers, fractions and decimals, ratios and percents, exponents, order of operations and basic geometry.

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Line rising across a coordinate grid

Algebra 1

Expressions, equations and inequalities, graphing lines, slope and systems of equations.

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  • Geometry
  • Algebra 2
  • Trigonometry
  • Precalculus
  • Calculus 1
  • Calculus 2
  • Statistics

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Calculators and Math Books

Guides to choosing a calculator and the math books that help most, sorted by course and grade.

About The Math Index

The Math Index is a free set of math lessons for high school and college students, and for the parents, teachers and tutors who help them. Lessons explain each idea in plain words and work through examples step by step.

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