12 加法 21 等于多少？
12 + 21 = 33
12加法21 等于 33
竖式演算
验算
- 用减法验算：33 − 21 = 12
- 用减法验算：33 − 12 = 21
相关题目
12 + 20 = 32
12 + 22 = 34
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12 + 23 = 35
12 + 24 = 36
12 + 18 = 30
12 + 25 = 37
12 + 17 = 29
11 + 21 = 32
13 + 21 = 34
10 + 21 = 31
14 + 21 = 35
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9 + 21 = 30
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2 + 31 = 33
3 + 30 = 33
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5 + 28 = 33
6 + 27 = 33
32 + 60 = 92
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22 + 40 = 62
45 + 22 = 67
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71 - 38 = 33