Calculate the formula result on the top of the screen, press and hold the "Tap" button at the bottom of the screen, and 9 numbers will appear randomly in the middle of the screen every second. You need to match the correct result, then release the "Tap" button. If your correct result is among the numbers that appear, you win, if not, it is a mistake. This not only tests your calculation ability, but also examines your hand-eye combination ability.