Math lessons that are actually complete
Every lesson explains the concept, shows why it works, walks through examples, and gives you practice problems with every solution step. Free, on one page, aligned to what US schools actually teach.
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- Early Math32 lessons
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- Percents7 lessons
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Every lesson is tagged to the Common Core standards it teaches, and shows the standard's full official wording. Browse all 509 standards to find lessons aligned to what you are teaching.
Lessons print cleanly. Use the print controls at the bottom of any lesson to produce a blank worksheet or a copy with the complete answer key. Everything is free to use in the classroom.
Latest lessons
- How to Solve Absolute Value Equations
Solve absolute value equations by splitting into two cases, why two answers appear, when there is no solution, and how absolute value inequalities differ.
- How to Solve Absolute Value Inequalities
Solve absolute value inequalities by thinking in distances: less than gives one stretch of the number line, greater than gives two rays pointing away.
- Adding and Subtracting Polynomials
What a polynomial is, how to read its degree and leading coefficient, why only like terms combine, and why subtracting means distributing the minus sign to every term.
- Arithmetic and Geometric Sequences
How to tell an arithmetic sequence from a geometric one, how to write each recursively and explicitly, and why the explicit rules are linear and exponential functions.
- Comparing Functions Across Tables, Graphs and Equations
How to compare two functions given in different forms, build a linear function from a table or a description, and read the rate of change from each one.
- Completing the Square, Step by Step
Learn completing the square: why the method works geometrically, how to handle a leading coefficient, and how it produces vertex form and the quadratic formula.