KenKen

About medium KenKen

The grid grows to 4×4 and subtraction enters the mix alongside addition. With 16 cells and more cage combinations, you can no longer brute-force every possibility in your head.

Start listing what each cage can hold. A "3−" cage with two cells in a 4×4 grid can only be (4,1) or (1,4). Cross-reference with what the row and column already contain, and you'll frequently pin a cell without touching any other cage. This list-and-eliminate approach scales to every difficulty level.