30 减法 21 等于多少？
30 - 21 = 9
30减法21 等于 9
竖式演算
验算
- 用加法验算：9 + 21 = 30
相关题目
30 - 20 = 10
30 - 22 = 8
30 - 19 = 11
30 - 23 = 7
30 - 24 = 6
30 - 18 = 12
30 - 25 = 5
30 - 17 = 13
31 - 21 = 10
29 - 21 = 8
32 - 21 = 11
28 - 21 = 7
33 - 21 = 12
27 - 21 = 6
34 - 21 = 13
26 - 21 = 5
10 - 1 = 9
11 - 2 = 9
12 - 3 = 9
13 - 4 = 9
14 - 5 = 9
15 - 6 = 9
86 - 8 = 78
42 - 8 = 34
87 - 39 = 48
50 - 36 = 14
86 - 69 = 17
72 - 5 = 67
2 + 7 = 9
1 + 8 = 9