The timer starts when you do.
Every row and column has a target at the end. Cross out numbers until what's left in that line multiplies to it.
Try it. Tap the number that doesn't belong.
Lines on the same board all keep the same count: two on the 5×5, three on the 6×6 and 7×7. The hard part is a line where more than one set fits. A 24 on the 5×5 could be 8 and 3 or it could be 4 and 6, and you won't know until you check the columns.
One tap crosses a number out. Tap it again and it gets circled instead, which is how you mark the ones you're sure about. A third tap clears it. Drag across a row of cells and they all get the same mark as the first one.
A target goes green as soon as what's left in its line multiplies to it. That doesn't always mean you picked the right numbers, and the columns will tell you if you didn't. Tapping a green target circles whatever you haven't marked. It works backwards too. Circle some numbers that hit the target and a tap crosses out the rest.
The board stays blank until you press Start, and the timer doesn't run before then.
Old puzzles are under the calendar icon at the top.
Keyboard: arrows move, space taps, X crosses out, K circles, Z undoes. Right-click circles too.
Each dot is a board size, with the 5×5 on the left, and it fills in once you've solved that one. Old puzzles don't count toward streaks.
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