No time limit. Start central number is 99999,tap Red square. Then number will minus 1-10. Red Square=1,Green Square=2,Blue Square=3,Aqua Square=4, Tap them to make them plus equal to the minus part. When right number will minus 1-10,when not then this round is over. Number's color will change to the last square you tap. If still confused you can press the T to watch tutorial. Thanks for you support and wish you have a good time.
