About 8×8 puzzles
An 8×8 is a KenKen-style math and logic puzzle — the genre also known as calcudoku or mathdoku — on a grid of 8×8 cells. Every row and every column holds the numbers 1 to 8 exactly once, and each outlined cage must reach its target using the operation shown. The board above is divided into 31 cages, 7 of which are single cells that hand you their values outright, with no cage larger than 3 cells. It has exactly one solution and needs no guessing.
The jump from 6×6 to 8×8 is bigger than it looks: 64 cells against 36, and eight candidates per cell instead of six. The arithmetic gets roomier — a three-cell cage can total anything from 6 to 21 — so the early moves lean more on elimination across rows and columns than on any single cage.
Want a bigger board before we publish them? The solver already takes any size from 4×4 to 9×9 — type in a puzzle you have and it will give you real deductive hints. Otherwise, today's dailies are live, and how to play covers the rules from scratch.