Binary, one bit at a time.
Switch bits on until they add up to the number. Then do it on a whole grid, where every row and every column has to match.
Row 1 target 13 , now 5
Then the grid
In the game, every row and every column is a binary number. One bit counts for both.
Row 1 target 5 , now 5 , matches
Row 2 target 6 , now 6 , matches
Row 3 target 3 , now 3 , matches
Column 1 target 6 , now 6 , matches
Column 2 target 3 , now 3 , matches
Column 3 target 5 , now 5 , matches
Free, no account, no ads. 3 to 8 bits.