This is a very light 3-eliminator game.
You just need to click the number to change, if there are 3 horizontal or vertical units are same number, then they will be eliminated and get score. so easy.
You can try to combine 4 or 5 same units to get more bonus, you can also try T, L shape.
If you have quick brain and hand, you can get more score.
Compare with your friends to see if who is the "fastest".
Keep simple!!!