30 加法 21 等于多少？
30 + 21 = 51
30加法21 等于 51
竖式演算
验算
- 用减法验算：51 − 21 = 30
- 用减法验算：51 − 30 = 21
相关题目
30 + 20 = 50
30 + 22 = 52
30 + 19 = 49
30 + 23 = 53
30 + 24 = 54
30 + 18 = 48
30 + 25 = 55
30 + 17 = 47
29 + 21 = 50
31 + 21 = 52
28 + 21 = 49
32 + 21 = 53
33 + 21 = 54
27 + 21 = 48
34 + 21 = 55
26 + 21 = 47
1 + 50 = 51
2 + 49 = 51
3 + 48 = 51
4 + 47 = 51
5 + 46 = 51
6 + 45 = 51
23 + 51 = 74
1 + 17 = 18
31 + 16 = 47
47 + 52 = 99
7 + 100 = 107
61 + 21 = 82
91 - 40 = 51
56 - 5 = 51