20 加法 1 等于多少？

20 + 1 = 21

20加法1 等于 21

竖式演算

20+121

验算

  • 用减法验算：21 − 1 = 20
  • 用减法验算：21 − 20 = 1

相关题目

20 + 2 = 22 20 + 3 = 23 20 + 4 = 24 20 + 5 = 25 20 + 6 = 26 20 + 7 = 27 20 + 8 = 28 20 + 9 = 29 19 + 1 = 20 21 + 1 = 22 22 + 1 = 23 18 + 1 = 19 23 + 1 = 24 17 + 1 = 18 24 + 1 = 25 16 + 1 = 17 1 + 20 = 21 2 + 19 = 21 3 + 18 = 21 4 + 17 = 21 5 + 16 = 21 6 + 15 = 21 4 + 93 = 97 91 + 4 = 95 49 + 40 = 89 1 + 13 = 14 45 + 44 = 89 5 + 52 = 57 67 - 46 = 21 29 - 8 = 21