10以内的加法+10以内的减法+10以内的加减混合+10以内连加+10以内连减+10以内加减混合+11~20的加减法+20以内加法（进位） 计算题
1.5 + 1 - 2 = 4
2.4 + 7 - 8 = 3
3.7 - 3 - 2 = 2
4.9 + 0 = 9
5.0 + 4 - 5 = -1
6.2 + 7 - 1 = 8
7.8 + 7 + 6 = 21
8.13 - 8 = 5
9.19 + 4 = 15
10.13 - 4 = 9
11.0 - 0 - 0 = 0
12.7 + 1 - 3 = 5
13.12 - 9 - 3 = 0
14.9 - 7 = 2
15.6 + 1 - 6 = 1
16.15 + 3 = 12
17.8 - 3 = 5
18.9 + 1 + 4 = 14
19.7 + 5 + 9 = 21
20.1 + 6 - 1 = 6
21.0 - 0 - 0 = 0
22.12 + 8 = 4
23.5 + 1 = 6
24.12 + 3 = 15
25.1 + 9 + 4 = 14
26.11 + 9 = 20
27.2 + 4 - 0 = 6
28.2 + 2 - 1 = 3
29.1 + 7 = 8
30.3 + 5 + 5 = 13
31.12 - 0 - 0 = 12
32.8 + 5 + 8 = 21
33.1 + 7 + 0 = 8
34.5 + 4 = 9
35.8 + 1 - 6 = 3
36.4 - 2 = 2
37.1 + 1 = 2
38.20 + 1 = 21
39.9 + 4 - 4 = 9