(共19张PPT)
整理和复习
11-9
12-9
13-9
14-9
15-9
16-9
17-9
18-9
11-8
13-8
12-8
16-8
15-8
14-8
17-8
11-6
16-7
15-7
14-7
13-7
12-7
11-7
13-5
12-5
11-5
15-6
14-6
13-6
12-6
11-3
13-4
12-4
11-4
14-5
11-2
12-3
20以内退位减法表
学 习 单
1.根据算式的排列顺序,把表格填写完整。
2.同桌之间确定一种观察方式,并在括号里打√。
横着( )竖着( )斜着( )
3.把你观察中的发现跟同桌一起交流。
20以内退位减法表
11-9
12-9
13-9
14-9
15-9
16-9
17-9
18-9
11-8
12-8
13-8
14-8
15-8
16-8
17-8
11-7
14-7
15-7
11-6
12-6
13-6
14-6
15-6
11-5
12-5
13-5
14-5
11-4
12-4
13-4
11-3
12-3
11-2
11
11
11
11
11
11
11
11
9
8
7
6
5
4
3
2
12
12
12
12
12
12
9
8
6
5
4
3
9
8
6
5
4
9
8
7
6
5
13
13
13
13
13
14
14
14
14
14
15
15
15
16
16
17
17
18
9
8
6
9
8
9
8
9
被减数不变,
横着看:
减数变小
13-7
16-7
12-7
16
7
15
12
7
13
7
7
11-9
11-8
11-7
11-6
11-5
11-4
11-3
11-2
2
3
4
5
9
6
7
3
8
12-9
12-3
12-4
12-5
12-6
12-7
12-8
5
4
6
8
7
9
被减数不变,减数变少,差变大。
13-5
11-9
12-9
13-9
14-9
15-9
16-9
17-9
18-9
11-8
12-8
13-8
14-8
15-8
16-8
17-8
11
12
13
14
15
16
17
18
9
9
9
9
9
9
8
9
11-7
12-7
13-7
14-7
15-7
16-7
11-6
12-6
13-6
14-6
15-6
11-4
12-4
13-4
11-3
12-3
11-2
11
12
13
14
15
16
17
11
12
13
14
15
16
11
12
13
14
15
11
13
11
11
8
8
8
8
8
8
9
7
7
7
7
7
7
6
6
6
6
6
5
4
4
4
3
3
2
减数不变,
12
12
13
竖着看:
被减数变大
14-5
14
5
12-5
11-5
5
12
5
11
11-9
16-9
17-9
18-9
12-9
14-9
13-9
15-9
2
3
3
4
5
6
7
8
9
11-8
13-8
12-8
15-8
14-8
17-8
16-8
4
5
6
7
8
9
减数不变,被减数变大,差也变大
11-9
12-9
13-9
14-9
15-9
16-9
17-9
18-9
11-8
12-8
13-8
14-8
15-8
16-8
17-8
11-7
14-7
15-7
16-7
11-6
12-6
13-6
14-6
15-6
11-5
12-5
13-5
14-5
11-4
12-4
13-4
11-3
12-3
11-2
11
11
3
2
12
12
4
3
5
4
5
13
13
14
15
16
17
17
18
7
8
7
9
8
9
16
15
14
6
6
9
8
8
8
8
8
8
8
9
9
9
9
9
9
9
被减数变大、减数也变大,差不变
斜着看:
12-7
13-7
(1)说一说你知道了哪些信息。
(3)谁能列个算式?
12-9=3(朵)
(2)要求这个问题怎么想?
(4)为什么用减法算?
(6)根据所给信息还可以提出哪些问题?
(5)解答正确吗?
问题:
谢 谢