Learning path

Work through the stages in order, or jump to the point that fits you now.

Stage

Junior

Connect playful ideas to reusable tactics for early competition problems.

Number Placement GraphsPlace numbers in circles or cells on a graph while satisfying equal-sum, side-sum, target-answer, or adjacency constraints.
5 problemsSign in to track
Chessboard ColouringClassic board-colouring problems where a simple colour or weight pattern proves an impossibility, or shows the right construction.
9 problemsSign in to track
Clock — Hours and MinutesExplore clock-hand angle problems: when the hands overlap, point at right angles, or line up in other ways. Touch and drag the clock to set…
3 problemsSign in to track
ColouringsColour grids, cube faces, vertices, and edges subject to neighbour and count constraints — hands-on entry to construction and proof.
13 problemsSign in to track
Column Arithmetic RestorationRestore damaged column calculations by finding the missing digits in addition, subtraction, and multiplication records.
14 problemsSign in to track
Divisibility by 11Alternating digit-sum rule and a proof exercise.
1 problemSign in to track
Divisibility by 2 and 4Quick tests using the last one or two digits; practice with interactive digit-placement puzzles.
2 problemsSign in to track
Divisibility by 3 and 9Digit-sum rules and puzzles that build fluency with multiples of 3 and 9.
4 problemsSign in to track
Divisibility by 5 and 10Last-digit tests for 5 and 10, with interactive fill-in puzzles.
2 problemsSign in to track
Doubling the MedianLearn how to apply the method of doubling the median in triangle geometry. Includes proofs and ratio problems involving triangle medians.
2 problemsSign in to track
Knight ReturnsExact-move knight return problems built around colouring invariants and closed walks in the knight graph.
4 problemsSign in to track
Magic SquaresA classic number puzzle where rows, columns, and diagonals all add up to the same magic sum.
8 problemsSign in to track
Matchsticks ProblemsMove or remove matchsticks to build target figures with no dangling sticks.
9 problemsSign in to track
Maximum Non-Attacking PiecesExtremal chessboard placement problems solved by combining upper bounds with constructions.
5 problemsSign in to track
River Crossing RiddlesClassic brain teasers where you transport items or people across a river while following specific rules to avoid dangerous combinations.
7 problemsSign in to track
Roman Numeral Matchstick EquationsMove one matchstick in a Roman numeral equation to make it true, or to keep it true.
11 problemsSign in to track
Water Pouring PuzzlesClassic brain teasers where you measure exact amounts using unmarked containers through filling, emptying, and pouring.
10 problemsSign in to track

Stage

Intermediate

Develop stronger structure, proof habits, and multi-step reasoning.

Fixed Point of a SimilarityInteractive geometry demo: scale, rotate, and drag a shape to see the invariant point appear, then try the guess-the-point challenge mode.
0 problemsSign in to track
Balance Scale PuzzlesClassic counterfeit-coin and balance-scale problems where each weighing splits the cases into three branches.
6 problemsSign in to track
CryptarithmsWord puzzles where letters represent digits in arithmetic equations. Each letter stands for a unique digit.
6 problemsSign in to track
Equations in IntegersSolve equations where the unknowns must be integers. Core techniques: factoring into integer divisor pairs, parity arguments, modular…
12 problemsSign in to track
Game Theory & StrategiesIn competitive games, the best outcome depends not only on your own decisions but also on the choices made by others. Strategic thinking…
15 problemsSign in to track
Knight's TourA chess knight must visit every square exactly once. Explore tours on 5x5 to 8x8 boards and the graph-theory ideas behind them.
4 problemsSign in to track
Mathematics in ChessAn overview of chessboard problems about parity, move graphs, extremal placements, exact-opponent attacks, and Knight's Tour, with focused…
15 problemsSign in to track
Other Chessboard ProblemsA pair of chessboard construction problems driven by row-column counts and Hamiltonian-style reasoning on custom move graphs.
1 problemSign in to track
Spot the Formula!Recognise and apply standard algebraic identities — difference of squares, square of a sum/difference, sum and difference of cubes, and…
10 problemsSign in to track
The Principle of Mathematical InductionMathematical induction is a powerful proof technique for establishing that a statement holds for all natural numbers.
13 problemsSign in to track