Their first sudoku.

Hand it over without checking first.

• Small grids, coloured numbers.

  4×4 and 6×6 puzzles, with each number always in its own colour. Every puzzle has exactly one answer, and none needs a guess.

• Wrong numbers show why.

  If a number doesn't fit, Teenydoku rings the number it clashes with, then hops it back out. There are no lives, timers or scores to lose.

• A star for every puzzle.

  Each solved puzzle puts a star in the jar, and the next one starts straight away. The puzzles are made on the device, so they never run out.

• Brothers and sisters can share.

  Each child picks an animal and keeps their own stars and puzzle. Settings sit behind a number written in words, which a young child can't read.