The multiplication formula is the mantissa formula. In fact, some primary schools in China are also teaching multiplication formula, which is not against the sky, but teachers in some areas are lazy and don't teach it because it is not included in the compulsory course. I only represent myself and talk about the various stages of the formula I have learned.

First, the first contact with the formula.

In the sixth grade, the teacher was showing him a double-digit mental arithmetic. We admired him very much, and then asked the teacher how he could calculate so fast. Then he told us that besides multiplication, there is also a power formula. As long as you work out the mantissa, you can work it out completely and accurately in your mind. I was particularly interested, so I learned the formula of power and wrote it down firmly.

Second, the formula was said by a junior high school teacher to be useless.

I don't test formulas, but it helps my calculation efficiency. On a field trip, the game interaction involved calculation problems, because I quickly worked out the formula, which naturally became the focus of the class. Of course, the students are curious about why I calculate so fast, so I show off that I have learned the formula of power.

Students are sure that the teacher is the most authoritative in their minds, so they ask the teacher what the formula is. The teacher didn't know whether he had never studied or forgotten, and said in a slightly sarcastic tone, "Students shouldn't idle around at work." I was isolated for a long time after I went out.

Third, contact multiplication formula again and compose children's songs.

Later, I got married, had children, and came into contact with early education and kindergarten, which I didn't have when I was a child. On an ordinary evening this summer, my son danced around in circles, chanting "11121, 1212484 ...". I was exposed to multiplication formula, so I was surprised that kindergarten was teaching it.

When asked about his son, he said that it was taught by his sister and teacher, so that the rhythm of jumping laps was particularly good and he would not meet jio…… ... ...

I can't help but fall into deep meditation, and I am sincerely glad that my son met such an enlightenment teacher.

My experience is very ordinary and I can't represent everyone. Although the multiplication formula is not in the textbook, there are many people who know it in China, mainly because some teachers are lazy and don't want to teach it.