Can solve many things. Like accounting. You go to the supermarket to buy two things, one is 35 yuan and the other is 20 yuan, so when you pay, you have to pay 35+20=55 yuan.

You can also calculate your age. For example, if a person is 35 years old and he has an uncle who is 20 years older than him, then his uncle is 35+20=55 years old.

You can also calculate the distance. For example, if you go out to pay a New Year call, you drive to your aunt's house for 35 kilometers, and then you drive to your uncle's house for 20 kilometers, then you walk 35+20=55 kilometers as soon as you * *.

You can count many things. You can think for yourself.