Maths charts

A times table printed as plain black digits is something you read. The same table with colour standing in for the size of the product is something you start to see: the diagonal of squares, the mirror symmetry either side of it, the way the twelve column pulls away from everything else. The arithmetic here is not new — the arrangement is.

Multiplication runs from 1 to 12. The hundred chart picks the primes out in colour, so their uneven scatter becomes visible rather than asserted. Roman numerals set out the subtraction rule and how years are actually written, instead of listing seven symbols and leaving the rest to guesswork.

They belong at a child's eye level: beside a desk, on the back of a bedroom door, in the corner of a classroom. A4 to read up close, A3 when it has to work from across the room.