Infinite Math vs Euclid Lab

That “I solved it!” feeling, all over again. A math app for grown-ups who solve for pleasure—not for any exam. From the wonder of primes and divisors to the crane-and-turtle puzzle, the Monty Hall problem, and even the legendary entrance exams of Japan's top universities— a collection of beautiful problems that make you feel "numbers are fascinating." ■ Made for you if you ・love numbers and logic puzzles ・enjoy giving your mind a workout in spare moments ・want to know not just the answer, but the idea behind it ・are done with exams, but want to rediscover the joy of math ■ Six categories, 55+ problems (more added over time) ・Number Theory & Puzzles … primes, divisors, Fibonacci, perfect numbers, and more ・Classic Problems … crane-and-turtle, Monty Hall, the Königsberg bridges, Pick's theorem, and more ・Elementary Exams … ferris-wheel logic, seesaw puzzles, and other gems ・Junior-High Exams … work, travel, concentration, and counting problems ・High-School Exams … symmetric expressions, probability, Euler's prime-generating formula ・University Exams … legendary stumpers like "Is tan 1° rational?" and "Prove π > 3.05" ■ Highlights ・Daily Problem … one fresh problem to tackle each day ・Sessions … test yourself with five problems at a time ・Explanations worth reading … not just the answer, but the background and the thinking ・Interactive figures … trace the Königsberg bridges or Pick's theorem with your finger ・Progress tracking … solved problems are recorded; aim to clear them all ・19 languages … enjoy these problems in Japanese, English, Chinese, Korean, and more Answers are simple multiple choice—and some figures come alive at your fingertips. Enjoy the world of numbers on your commute, on a break, or before bed.

Explore the 48 propositions of Book I of Euclid’s Elements through reading, construction and proof practice. Euclid Lab separates proposition reading, straightedge-and-compass work and reasoning so you can focus on one activity at a time. Arrange supplied proof blocks to connect premises to conclusions. Scored exercises use semantic checks of geometric relationships and logical dependencies, not the appearance of a drawing or AI grading. Progressive hints and complete solutions, shown on request, help when you get stuck. I.7 currently offers unscored reading, exploration and notes. Freehand notes are also unscored and are not automatically verified as correct proofs. Foundations and I.1–I.12 are free. I.13–I.24 and I.25–I.48 are separate, one-time in-app purchases. Buying one pack does not unlock the other. No subscription is required. Learning progress and notes are stored locally on your device. Learner profiles are not Apple Accounts, and no Euclid Lab account registration is required. Restore Purchases restores eligible content access; it does not synchronize learning progress.