By using the method of supplementing ten, the carry addition within 20 is transformed into the familiar problem of 10 plus several, thus simplifying the complex and making simple calculations.

For example:

Calculate by ten: 9+6.

Solve the problem as follows:

Divide 6 into 1 and 54, because 9 adds up to 10 and lacks 1, so divide by 1.

So 9+6, the decomposition calculation is 9+ 1= 10, and finally 10+5= 15.

Extended data

The formula for adding up to ten is: look at large numbers, divide them into decimals, add up to ten, and add up the remainder. Clap your hands, children. Let's sing ten songs. One equals nine, two equals eight, three equals seven, four equals six and five equals ten.

In fact, the "plus ten method" is the basis of our oral and written addition and subtraction. Learning it well can improve the calculation speed of our addition and subtraction. Because our multiplication and division method also uses the calculation of addition and subtraction, it also affects the calculation speed of multiplication and division method to some extent.

When the product of three-digit multiplication is added with two-digit and ten-digit respectively, students' calculation speed is slow and they often make mistakes. Similarly, when calculating division, the dividend is subtracted from the product of divisor and quotient. Addition and subtraction are everywhere in our life and study. If these basic knowledge is not enough, it will directly lead to the mistakes of multi-digit addition and subtraction and multi-digit multiplication and division in middle school, and also lead to a series of mistakes in decimal calculation in high school.