What's the interesting story about the number 1 ~ 9?

The interesting story of the number 1 ~ 9 is as follows:

When Gauss was still in the second grade of primary school, one day his math teacher wanted to use class time to deal with some personal affairs, so he planned to give the students a difficult problem to practice. His topic is:1+2+3+4+5+6+7+8+9+10 =?

Because addition has just been taught, the teacher thinks it will take a long time for students to solve this problem. I can also take this opportunity to deal with unfinished business. But in the blink of an eye, Gauss had stopped writing and sat there doing nothing. The teacher saw it and called Gauss angrily.

But Gauss said he had figured out the answer, which was 55. The teacher was startled and asked how Gauss worked it out. Gauss replied, "I just found out that the sum of 1 and 10 is the sum of1,2 and 9,1,3 and 8,1/kloc-0. And because11+1+11+11= 55, that's how I worked it out. " Hearing this, the teachers and students all gave Gauss a thumbs-up. Later Gauss grew up and became a great mathematician.

Simple method of induction in primary school mathematics

1, extracting common factor: This method actually uses multiplication and division to extract the same factor, and the remaining items in the exam are often added and subtracted, and an integer will appear.

2. Borrowing borrowing method: When using this method, you need to pay attention to observation and find the law.

3. Split method: Split method is to split a number into several numbers for the convenience of calculation.