MathGrid (PuzzleMadness)

A MathGrid looks like a small crossword in which every entry is a sum such as 10 / 5 = 2, reading across or down, with the entries crossing at shared cells. Some cells are filled in from the start. The rest are blank, and the numbers and operators you need (plus, minus, times and divide) sit in a row of tiles under the grid. Every tile has to be used, and there is only one way to place them all so that every calculation is right.

It rewards a mix of mental arithmetic and crossword-style cross-checking: a tile that fits one sum also has to suit the sum it crosses. The Medium grid on 28 October 2026, for example, had 22 tiles to place, numbers from 3 to 75 among them.

PuzzleMadness is a free puzzle website run by Dewi, a software developer who started out making games for the PlayStation 2, Nintendo Wii and DS and now builds the site as a hobby. It carries dozens of puzzle types, from classic sudoku to newer logic grids, and each one gets its own dated puzzle every day at each difficulty. MathGrid comes in Easy, Medium, Hard and Tough versions. The Mixed page adds a fifth grid with its own tiles, at a level that changes from day to day, and the same day's MathGrid puzzle is shared by everyone who opens it.

The site checks your grid as you go and tells you when it is finished; it does not publish solutions. Each completed puzzle earns a score, and scores feed a monthly and an all-time MathGrid leaderboard, where only your best attempt at a puzzle counts. Older days stay in the archive, so a missed puzzle can still be played later and still counts toward the current month. Playing needs no account; a free registration gives you a username on the leaderboards and a cloud save. The pages carry adverts.