ColorfulSum

A puzzle app for children to adults.

The puzzle is also known as KenKen or Keisan-Block (in Japanese).
It's a variant of Sudoku, but requires a bit calculation.

The rule is as follows; Fill all cells with integers from 1 to 4 so that:
- In each row/column, every integer appears exactly once.
- In each colored block, the sum of assigned integers should be = the small number attached to it.

The app has four levels from 4x4 to 7x7, and each level contains 16 puzzles. Have fun!