Self-Learning Lessons
Pick a topic. Try the problems first, watch how the trick works, then practice on your own.
Mental Math
Build fast, in-your-head number sense by reshaping numbers instead of computing the long way.
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Mental Math · Friendly Numbers
Bend any add-or-subtract problem into a friendly number and finish it in your head before your pencil even moves.
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Mental Math · Multiplication Tricks
Big multiplications look slow, but each one hides a friendly cut that makes it easy. Try each problem first, then watch the trick fire.
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Mental Math · Divisibility
Big numbers look scary to divide, but every divisor only peeks at one tiny tail — try each problem first, then learn the test that cracks it in your head.
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Mental Math · Percent Sense
Every percent is just a few clean slices carved off one bar — try each one in your head first, then watch the trick that makes it easy.
Problem Solving
Turn a tricky story into an equation you can solve — by decoding, assuming, swapping, or undoing.
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Age & Gap Problems
Age puzzles look hard because the numbers keep changing — but one thing never moves. Try each problem first, then watch the Constant Crew reveal the trick.
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Chicken & Rabbit Problems
Two kinds of things, one total count, one total of legs or wheels or sticks — pretend they are all one kind, then swap to fix. Try each problem first, then watch the trick.
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Excess & Shortage
Two plans for the same supply — one leaves extras, one comes up short, or both, or the speeds change. Every disguise hides the same bridge: the gap between the plans equals the per-group amount times the gap in groups. Try each problem first, then watch the trick.
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Working Backwards
When a problem hands you the ENDING and hides the START, try undoing the chain yourself first — then watch how starting at the end cracks it open.
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Substitution Arithmetic
A custom symbol is just a recipe waiting to be substituted.
Patterns & Sums
Spot the rule inside a run of numbers, then sum or extend it without grinding through every term.
Counting Ways
Count gaps, arrangements, and shares systematically — without listing every case by hand.
Shape & Space
Reason about length, angle, and area — then bridge from a picture to an algebraic identity.
Reasoning & Data
Pull the decisive value off a chart, then find the best possible answer at a constraint’s edge.
