The methods of teaching children to subtract within 20 days are painting, tree stick and carry. 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.

Trick: If you subtract 24 from 5 of 15 to get 4, the result is 1, and then subtract it from 10 to get 9, which is a unit, and the 2 of 10 digit is borrowed, and the calculation of 10 digit becomes1-. If ten people want to continue to abdicate, repeat.

There are generally two methods, "counting method" and "digital reasoning method". Digital reasoning can be divided into "breaking ten", "leveling ten", "trying to add and subtract" and "reducing more and adding more".

1, drawing method. Draw some animals or fruits to increase interest and arouse children's enthusiasm. Picture method, with some beautiful pictures, learn while playing to improve children's interest.

2, the tree stick method. Draw a tree stick on the paper, which is clear and easy for children to understand. Finger method, let children use their own hands to index.

3. Carry method. Let the children do the calculations and learn from 10 to 1. The above methods are gradual, patient, encouraging and supporting children.

Subtraction. It is a basic arithmetic operation. The operation of subtracting one quantity from another is called subtraction, and the result becomes difference. Given the sum of two addends and one of them, the operation of finding the other addend is called subtraction. The symbol of subtraction is, read minus. Used to calculate decrement.

Subtraction doesn't have to be difficult, but it can be simple. This method is suitable for preschool and first-grade children. For example, if 24 minus 8 equals 16, you can think of it this way: if you borrow 14 minus 8, first subtract 8 from 10 equals 2, then 4 plus 2 equals 6, and the difference of one digit must be 6, so the calculation is simple.

That is to say, after borrowing a seat, first reduce the removed digits, and then add the reduced digits to the reduced digits, so that ten digits are not difficult. However, the premise is that the minuend unit must be smaller than the minuend unit to be simplified.