Sudoku4x4

It is a puzzle game in which numbers 1 to 4 are arranged in a 2×2 block, 4 squares vertically and 4 squares horizontally.
Recommended for people who have difficulty playing normal 9x9 Sudoku or who want to play in a short amount of time.
All 4x4 Sudoku puzzles are presented, and if you can solve all the problems in this app, you should be able to solve any 4x4 Sudoku.
A total of 108 problems will be presented.