Clap your hands, children. Let's sing ten songs. One equals nine and two equals eight. Three equals seven and four equals six. Fifty-five adds up to ten. "The most important thing to remember in the formula of addition is that large numbers are kept in mind and decimals are counted. For example: 4+2, keep 4 in mind, add up 5 and 6, and then get the result that 4+2=6.
Make up ten formulas:
19 19 good friend 1 9
2828 hand in hand 2, 8
Three, seven, three, seven are so close.
Four four six four six.
5555 1 hand 5,5
Remember large numbers in your mind and decimals in your hand.
Algorithm prompt:
1, two numbers add to keep the number unchanged: if one of the two added numbers increases, the other decreases, one increases and the other decreases.
When two numbers are added, one of them remains the same. If another number changes, this number will also change, and the result will change as much as the addend.
3. Add the two numbers and exchange positions to get the same number.