Mathematical operation itself is rather boring and abstract, such as 1+ 1=2, and the final result is that 2 can't be 3. Children must accept and remember that conditioned reflex, step by step, practice makes perfect, and practice repeatedly, which is unreasonable. There is no shortcut. Only in this way can the speed and accuracy be improved. You can try it by the following steps:

The addition and subtraction within 1 and 10 need to be simple, fast and accurate, which is the foundation;

2, less first, then more, starting with the addition within 20, step by step; ?

Add OK within 3.20 minutes, and then practice subtraction; ?

4, addition and subtraction can be done, and finally practice the addition and subtraction together.

For example, 15-8, 5 is not enough to subtract 8. The complement of 3.3 obtained by subtracting 5 from 8 in reverse operation is 7, and the answer is 7. Formula: three MINUS seven. Not bad for my children. Even better than subtraction or addition and subtraction in books. I picked up Montessori mathematics again, and the method in it is also good.

Extended data:

"+"is a plus sign, the numbers before and after the plus sign are addends, "=" is an equal sign, and the numbers after the equal sign are sums.

100 (addend)+(plus sign) 300 (addend) = (equal sign) 400 (sum)

Additive commutative law

a+b=b+a

For example: 8+1=1+8 = 9100+2 = 2+100 =102.

associative law of addition

:a+b+c=a+(b+c)

Example: 7+4+1= 7+(4+1) = (7+4)+1=1210-5+2 = (10)

Baidu Encyclopedia-Supplement