1, 1 in the unit means 1, and whatever is in the unit is what it is.
2. 1 of the tenth digit means 1 10, and several digits of the tenth digit means dozens.
3. The hundredth 1 means 1 100, and the hundredth number means hundreds.
Firstly, the concept of borrowing is explained from the simple two-digit MINUS one-digit borrowing.
For example:
38-9=?
In order to improve children's interest,
Let's take the minuend as the number of chocolates that children like.
Eight in the unit represents eight pieces of chocolate in bulk.
The tenth number 3 means 3 boxes, each box is 10 yuan, that is, 30 yuan.
Let the children imagine that they are going to take out nine chocolates now.
But each seat is only 8 yuan, which is not enough.
What should we do?
Let's take out 1 box from the tenth place and open it, and add 10 and eight from the eighth place.
In this way, the ten digits are missing 1 box, which is two boxes.
One unit is 18 yuan,
Subtract 9 blocks from 18 block, leaving 9 blocks.
Namely: 38-9 = 29
Extended data:
Subtraction by abdication, a special mathematical term, can also be called subtraction by borrowing. That is, when two numbers are subtracted and the number of digits to be subtracted is not enough, borrowing the previous digit is equivalent to adding 10 to this digit, and then calculating.
Tips:
Calculated on the draft paper: 5+05 of 65438 minus 4 of 24, the result is 1, and then subtracted by 10 to get 9, which is a unit, while 2 of the decimal digits is borrowed, and the calculation of the decimal digits becomes 1- 1, which is 0 and the result is 9. If ten people want to continue to abdicate, repeat. Of course, this can't be written in a formal place.
Reference: Baidu Encyclopedia-abdication subtraction