One Factorial: Math Olympiad

One Factorial is a collection of original, competition-style math problems for capable 4th and 5th graders who are ready for a real challenge — the kind of thinking found in math olympiads and entrance exams, made approachable and fun. Great practice for students preparing for elementary math competitions such as Math Kangaroo, MOEMS, and AMC 8 — and just as good for homeschool enrichment, a gifted and talented program, or any child who simply loves a hard puzzle. These aren't repetitive drills or worksheets. Contest math is a different sport: each problem rewards clever reasoning, spatial thinking, and clear strategy over rote calculation. Kids learn to slow down, spot patterns, and work a problem all the way out — the problem-solving skills that carry into pre-algebra and beyond. WHAT'S INSIDE • Original competition-style problems across four topics — arithmetic & number sense, logic & reasoning, geometry, and non-standard problem solving — with new problems added regularly. • Math word problems, logic puzzles and brain teasers pitched at grade 4 and grade 5, at three difficulty levels, so a child can start gently and climb. • Original hand-drawn diagrams for geometry and puzzle problems, animated so you can see each figure built up piece by piece. • A Strategies library — clear explainers for named techniques like the pigeonhole principle, working backwards, Gauss's summation trick, and divisibility rules. • Encouraging, skill-specific feedback that adapts its tone to each problem's difficulty. • Step-by-step solutions revealed when you're ready, so kids can check their reasoning. • A "Solved" tracker so students can see their progress and revisit unsolved problems. • "Another like this" — every problem links to more of the same kind, so a shaky idea can be drilled until it sticks. • A timed exam mode, for practicing under real competition pressure. BUILT FOR FAMILIES, HOMESCHOOLERS AND CLASSROOMS • No account or login required. • No ads, no third-party advertising, and no behavioral tracking. • Works fully offline — practice in the car, on a plane, anywhere. • Progress stays on the device. TRY BEFORE YOU BUY One problem at every difficulty in every topic is free, so you can try the real thing — diagrams, hints and worked solutions included — before you decide. A single one-time purchase unlocks everything else, with no subscription, ever. Whether your child is preparing for a math competition, an entrance exam, or simply loves a good puzzle, One Factorial turns challenging math into something to look forward to. One Factorial is an independent app and is not affiliated with, authorized, or endorsed by Math Kangaroo in USA, NFP, MOEMS, or the Mathematical Association of America. All problems are original and written for this app.