Score
0
Time
90s
Best
—
Arithmetic logic puzzle. Fill a 4×4 grid with 1–4 so every row and column has no repeats, and each outlined cage hits its target with the shown operation. Solve as many as you can in 90 seconds.
Tap a cell to cycle its number 1, 2, 3, 4, then empty. Every row and every column must contain each of 1 to 4 exactly once, just like Sudoku.
The grid is divided into cages outlined in bold. The little label in a cage's corner is a target followed by an operation. The numbers you place inside that cage must combine to make the target: 6+ means they add to six, 8× means they multiply to eight, 2− means the two numbers differ by two, and 3÷ means one divides the other to give three. A cage with a bare number is simply that value.
A cell turns red when it repeats a number in its row or column, or when a full cage misses its target, so mistakes are easy to spot.
Finish a grid to score and a new one appears instantly. Rack up as many as you can before time runs out.
Single-cell cages are free numbers, so place every one of them first. They behave like Sudoku givens and instantly remove a candidate from their whole row and column, often unlocking the cells next door before you have done any arithmetic at all.
Learn the cages that have only one arrangement on a four-grid. A two-cell 3÷ can only be 1 and 3, a 4÷ must be the lonely pair that divides cleanly, and a subtraction of 3 can only be 1 and 4. A three-cell cage adding to a small or large total is similarly pinned. Filling these forced cages turns the puzzle into ordinary row-and-column logic.
Remember that the digits 1 to 4 always sum to ten and multiply to twenty-four across a full line. If a cage spans most of a row you can subtract its target from ten, or divide twenty-four by it, to read off what the leftover cells must be. This line-total trick cracks many grids that look stuck.
In the timed mode, scan for the most constrained cage rather than starting top-left. Place everything forced, let the no-repeats rule cascade, and only guess as a last resort — a wrong digit usually shows up as a red cell within a move or two, so you can back it out quickly and keep your pace.