11~20的加减法+20以内加法（进位） 计算题
1.20 - 8 = 28
2.18 + 7 = 25
3.18 + 3 = 21
4.17 + 8 = 25
5.13 - 7 = 6
6.15 - 8 = 7
7.12 - 4 = 16
8.12 - 7 = 5
9.15 + 9 = 24
10.16 + 9 = 25
11.19 + 5 = 24
12.20 - 9 = 11
13.12 + 5 = 17
14.17 + 6 = 23
15.19 - 8 = 27
16.19 + 7 = 26
17.15 + 3 = 18
18.19 + 5 = 24
19.12 - 3 = 9
20.12 + 3 = 15
21.14 - 2 = 16
22.11 - 1 = 10
23.15 + 8 = 23
24.14 - 0 = 14
25.13 - 9 = 22
26.13 + 6 = 19
27.19 - 9 = 28
28.14 - 9 = 23
29.15 - 5 = 20
30.20 + 3 = 17
31.15 + 9 = 24
32.15 + 5 = 20
33.19 + 6 = 25
34.18 - 6 = 24
35.18 - 7 = 25
36.13 + 7 = 20
37.17 + 2 = 15
38.13 + 6 = 19
39.18 + 2 = 20