IB Math RevisionIntermediate competition-style problems (ages 13 to 16)
173 problems in the age band of the UKMT Intermediate Mathematical Challenge and the MAA AMC 10. GCSE / IGCSE / Class 9–10 content used in unfamiliar ways: modular arithmetic, clever counting, circle and area geometry, conditional probability. Every problem is original — written by us, not taken from a real paper — with two hints, a full solution, a note on why the method works and where the idea leads.
All 173 are free, with full solutions.
Answer a problem to track what you have solved.
Choose a topic
Number theory
Divisibility, primes, remainders and digits.
All free, with solutions
32 problems →Combinatorics
Counting arrangements, paths, subsets and tilings.
All free, with solutions
30 problems →Geometry
Angles, areas, circles, lattice points and solids.
All free, with solutions
28 problems →Algebra
Equations, sequences, functions and inequalities.
All free, with solutions
29 problems →Probability
Dice, cards, areas and expected values.
All free, with solutions
26 problems →Logic
Truth-tellers, calendars, games and reasoning puzzles.
All free, with solutions
28 problems →Stuck? Learn a strategy
Each problem is tagged with the strategy that cracks it. The problem-solving strategy guides explain ten of them with worked examples: organised cases, count the opposite, working backwards, invariants, extremal principle and more.
Junior problems (ages 11 to 13) · Senior problems (ages 16 to 18) · Olympiad-style problems (ages 15 to 18) · Where next after these? · Competitions, past papers and problem of the week