About Math Crosswords
Math Crosswords is a free number puzzle game made and run by Vladimir Duțan. It started as a way to get the satisfaction of a word crossword out of plain arithmetic: a grid where every row and column is an equation, and every number you place has to work in two directions.
How the puzzles are made
Every grid is built by a generator written for this site, not copied from a book or another app. It lays equations across and down so they lock together on shared numbers, picks which numbers to hide, and then checks the result before you ever see it.
Two checks matter most. First, the puzzle must have exactly one solution: the generator tries every way the bank tiles could fill the blanks and throws the grid away if more than one works. Second, the puzzle must be solvable by reasoning alone. A built-in solver works through it the way a person would, and if it ever has to guess, the grid is discarded.
The same solver writes the step-by-step solutions in the daily archive, so each explanation follows the path a careful player can actually take.
How difficulty is set
Difficulty has two parts. The arithmetic: Easy uses addition and subtraction up to 30, Medium adds multiplication up to 99, Hard adds division and longer two-operator equations, and Expert goes up to 120 with the most blanks.
The reasoning: Easy always has an equation with a single blank to fill next. From Medium up, there are moments where no equation has a single blank left, and you have to compare which tiles could fit where. Expert needs that at least twice and the longest chain of steps. The guide explains both techniques.
The daily puzzle
Each day brings four new puzzles, one per level, the same for every player. Longer lines follow ordinary order: multiplication and division before addition and subtraction, and every step is a positive whole number. The first time a day is opened, that grid is saved. A saved grid that still follows that order is the one everyone plays. Past days stay playable in the archive, and their answers and written solutions appear the next day.
What stays the same
Accounts are optional; you can play every puzzle as a guest. Signed-in players earn points and can appear on the leaderboard by display name, never by email. Ads keep the site free, and they never cover the puzzle you are playing.
Contact
Found a bug, a puzzle that seems wrong, or have an idea? Use Report a problem / Feedback in the footer or on a puzzle, or write to vlad.dutan@gmail.com. See also the privacy policy and terms.