Number Puzzle: Slide to Sort

Classic simple game everyone used to play once.
Slide numbers to sort them in ascending order.
Arrange numbers on 3x3, 4x4, or 5x5 board.

Intellectual puzzle comes in neat and clean design.

Let's make them green!
Slide numbered tiles in random order with one tile missing.
Every generated puzzle in this game can be solved, so don't worry.
You can definitely sort them in order in the meantime.

Number Puzzle can be called by many other names
e.g. Gem Puzzle, Boss Puzzle, Game of Fifteen, or Mystic Square.

Number Puzzle improves player's logic. It's an excellent brain game.
It can be played for education.