CrossMath Number Challenge

CrossMath Number Challenge is a crossword of arithmetic. Equations run across and down and cross each other, so every number you place has to be right in two directions at once. Fill the white cells, watch each equation turn green, and solve the whole grid.

Every puzzle is built on your phone by a constraint solver and has exactly one solution, so you can always reason your way to the answer. Pick your level: Easy grids use addition and subtraction with numbers up to 9, while Expert grids are 9×9 with all four operations and numbers up to 99.

The rules are simple and the app explains them in a short tutorial: equations are read strictly from left to right (and top to bottom), every step must stay a positive whole number, and division must be exact. No decimals, no negative numbers, no guessing about precedence.

Features
• Four levels: Easy (5×5, 1–9), Medium (5×5, 1–20), Hard (7×7, 1–50), Expert (9×9, 1–99)
• Nine grid layouts with two-, three- and four-operand equations
• Unlimited practice: a fresh puzzle every time
• Daily challenge: the same puzzle for everyone, one scored attempt per day, build your streak
• Timed mode: solve as many puzzles as you can in five minutes
• Tap a cell to light up every equation it belongs to
• Instant feedback: complete equations turn green or red
• Hints that point to an equation first, and reveal a cell only if you ask again
• Undo, erase, check and restart
• Statistics: puzzles solved per level, best and average times, streaks and history
• Progress is saved after every entry and restored when you come back
• Works completely offline, no account needed
• Light and dark themes, scalable text and TalkBack support
• Optional sound effects and vibration

CrossMath Number Challenge is free to play and contains ads. There are no subscriptions, paid unlocks or in-app purchases.

Recent changes:
Version 1.0.0
• First release: practice, daily challenge and timed mode
• Four levels with unique-solution puzzles generated on your device
• Statistics, streaks, hints, undo and a full tutorial
• Works offline; light and dark themes