Maths · Divisibility
HCF and LCM you can finally see: each prime factor is a block
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Tap multiples and primes, break numbers into blocks and build the HCF and LCM
Every number can be written as a product of primes: 12 = 2 · 2 · 3. Here each prime factor is a coloured block (2 blue, 3 green, 5 orange, 7 purple…), so each number is a row of blocks.
The highest common factor (HCF) is the blocks both numbers have: the common ones, with the lowest power. The lowest common multiple (LCM) puts them all together without repeating the shared ones: for each prime, the longest row. There are no options: you build the HCF and LCM with blocks (+ and − for each prime), break numbers by dividing them by primes and tap the multiples and the primes. When you answer, the blocks that count light up.
There are also divisibility rules, numbers that look prime but are not (91 = 7 · 13) and word problems: if things “coincide again” it is an LCM; if you cut or share into equal parts as big as possible, an HCF.
⏱️ 90s · Correct +10 and +6s · Wrong −5s
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