The checking method of addition: one is to exchange the position of addend and recalculate; One is the sum minus one addend equals another addend. The check calculation method of subtraction: one is that the difference addition and subtraction is equal to the minuend; One is that the subtraction of the minuend equals the subtraction. Calculation of multiplication: product divided by one factor = another factor. The two methods of division calculation are quotient multiplication and quotient division, and the dividend is divided by quotient. Division is one of the four operations. The product of two factors and a non-zero factor is known.

For the calculation of addition, for example, 3+4=7, subtract "minus" from "sum" to see if the result is 3.

For the calculation of subtraction, for example, 4-2=2, you only need to check the difference and whether the subtraction is the minuend, that is, "2+2=4".

For the calculation of multiplication, for example, 1×4=4, just verify that 4÷4 = 1.

For the calculation of division, such as 4÷ 1=4, in turn, verify whether 4× 1 is equal to 4.