AMC 8 / MathCounts
Competition
Contest problem solving for AMC 8 and MathCounts: the ideas, the tricks, and timed practice in the real format.
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Number Theory Toolkit
Unit 1 · Number Theory Toolkit
0 of 6 units complete
- 1Unit 1Number Theory Toolkit5 parts · about 12 min
Number Theory Toolkit
The number tricks that win AMC 8 points fast: digit-sum tests, prime factorizations that count divisors in one line, LCMs for things that line up again, and the last digit of a number too big to write down.
- 2Unit 2Counting & Probability5 parts · about 12 min
Counting and Probability, AMC Style
Multiply choices, count the opposite, split into tidy cases without double counting, and turn every probability question into favourable over total, with tables and trees to keep it honest.
- 3Unit 3Algebra & Manipulation5 parts · about 10 min
Algebra and Manipulation
Turn words into equations, keep a balance level while solving, use ratios and "parts", and spot the factoring tricks (like 2026² − 2025²) that make AMC arithmetic instant. Plus the average-speed trap.
- 4Unit 4Geometry Essentials5 parts · about 12 min
Geometry Essentials
Angle chasing with parallel lines, similar triangles that scale everything, areas found by subtracting what you do not want, and grid shapes measured with coordinates (and a surprising formula by Pick).
- 5Unit 5Clever Counting & Logic5 parts · about 11 min
Clever Counting and Logic
Count without listing: multiples in a range, grid paths, handshakes and diagonals, and Venn diagrams that stop you counting anything twice. Plus a few logic puzzles of the kind the AMC 8 loves.
- 6Unit 6Why the Formulas Work5 parts · about 12 min
Why the Formulas Work
Stop memorising and start seeing. Prove the triangle angle sum with one parallel line, Pythagoras by rearranging four triangles, Gauss's sum with a staircase, and every area formula from the humble rectangle.