2.1十几减9（一）课件一年级下册数学人教版(共16张PPT)

(共16张PPT)
理解用“破十法”算“十几减9”的道理，会正确地口算十几减9的退位减法。
15 – 3 = 12
圈一圈，算一算
5-3=2
10+2=12
15 - 9
？
15 - 3
15 - 9
15 - 9 = 6
10 - 9 = 1
1 + 5 = 6
11
- 9
10 - 9 = 1
1 + 1 = 2
用 摆一摆，算一算
= 2
用 摆一摆，算一算
10 - 9 = 1
1 + 2 = 3
12 - 9 = 3
5
9
1
9
1 - = 2
2
9
1 - = 6
10 - 9 = 1
1 + 5 = 6
10 - 9 = 1
1 + 1 = 2
1 - = 3
10 - 9 = 1
1 + 2 = 3
圈一圈，算一算
10 - 9 = 1
1 + 4 = 5
1 4 - 9
= 5
课本第10页做一做第2题
17 - 9 =
10 - 9 = 1
1 + 7 = 8
圈一圈，算一算
8
课本第10页做一做第2题
算一算，连一连
1 1 - 9
1 2 - 9
1 5 - 9
1 7 - 9
2
4
3
6
7
8
1 1 - 9 = 2
读一读
1 2 - 9 = 3
1 4 - 9 = 5
1 5 - 9 = 6
1 7 - 9 = 8
说一说
1 4 - 9 = 5
1 2 - 9 = 3
1 7 - 9 = 8
1 1 - 9 = 2
1 5 - 9 = 6