Good friends1919,2828, hand in hand, 3737 is really close, and 4646 will go together. Make a pair of hands in half.

Look at large numbers, divide them into decimals, make up ten, and add up the remainder. Remember large numbers in your mind and decimals in your hand. 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 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 making up ten is simple and easy, and the thinking process includes "looking at large numbers, dividing by two (except decimals), dividing by three and adding by four".

3. Look at large numbers, divide them into decimals, make up ten, and add the remainder.