The formula of borrowing ten method: ten MINUS nine, plus1; A dozen MINUS 8, a few plus 2; A dozen MINUS seven, a few plus three; A dozen MINUS six, a few plus four; A dozen MINUS five, a few plus five; A dozen MINUS four, a few plus six; A dozen MINUS three, a few plus seven; A dozen MINUS two, a few plus eight; A dozen MINUS 1, a few plus 9.
The method of filling ten is the basic idea of carry addition within 20. By using the method of "adding to ten", the carry addition within 20 can be transformed into the familiar problem of 10 plus several, which is difficult to simplify.
Primary school mathematics learning formula
1, add up to ten methods.
Good friends1919,2828, hand in hand, 3737 is really close, and 4646 will go together. Make a pair of hands in half.
One plus nine, ten tadpoles, two plus eight, ten old ducks, three plus seven, ten old hens, four plus six, ten golden monkeys, five plus five, and ten big tigers.
Think of 1 when you see 9, 2 when you see 8, 3 when you see 7, and 4 when you see 6.
When you see the big corner decimal system, switch the two numbers first.
Carry addition within 2.20
(1) Children should remember "9 to 1", "8 to 2", "7 to 3", "6 to 4" and "5 to 5".
(2) The method of ten plus one is simple, and the thinking process includes "one look (at large numbers), dichotomy (at decimals), three plus ten, and four plus".
(3) Look at large numbers, divide them into decimals, add them to ten, and add the remainder.