Learn easily, make progress happily, and harvest the tree of wisdom happily!

Split method and ten-break method

Breaking ten methods: add nine and subtract one, add eight and subtract two, add seven and subtract three, add six and subtract four, and add five to see five.

Digital splitting method

9+6=9+( 1+5)=(9+ 1)+5= 15

156, 246, 336, 426, 5 16; The ingredients of 6 are not lacking.

167, 257, 347, 437, 527, 6 17; Remember the composition of 7 carefully.

178, 268, 358, 448, 538, 628, 7 18; Write down the composition of 8.

189, 279, 369, 459, 549, 639, 729, 8 19; All the ingredients of 9 are there.

1910,2810,3710,4610,5510,6410,73/kloc.

Collect ten songs

19 19 good friends, one plus nine, ten tadpoles, two plus eight, ten old ducks, three plus seven, three plus seven, ten old hens, four plus six. Four plus six, ten golden monkeys, 50/50 to make a pair of hands. Five plus five, ten big tigers.

Good and evil tree

Learn easily, make progress happily, and harvest the tree of wisdom happily!

Carry addition within 20

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

Backward reduction method

The abdication subtraction should be kept in mind, starting from the unit; Who is not enough to retire, don't forget to add ten to the standard; If the interval is 1, it is best to remember that 0 becomes 10. Successive abdication subtraction

When you see 0, go and see which one has it. Borrowed and walked back, 0 is a bit like 9.

I can share what I know. For example, 1: when you add 8+5, you think of 2, so 5 can be divided into 2 and 3, and 8 and 2 can be composed of 10,/kloc-0+3 =13, so 8+5 = 13.

For example, 2: minus 15-9. The first one: 15 can be divided into 10 and 5, 10-9 = 1 = 6, so15-9 = 6; The second type: 9 can be divided into 5 and 4, 15-5 = 10, 10-4 = 6, so 15-9 = 6.