2-digit addition problems
Thirty sums of two two-digit numbers, most of them with a carry. Do them in your head, as fast as you can.
30 problems · answer key ·
Problems
Name: ________________ Time: ________
- 37 + 25 =
- 55 + 63 =
- 28 + 52 =
- 71 + 64 =
- 79 + 75 =
- 18 + 95 =
- 71 + 31 =
- 46 + 98 =
- 22 + 74 =
- 23 + 41 =
- 71 + 20 =
- 53 + 15 =
- 83 + 95 =
- 86 + 52 =
- 94 + 18 =
- 29 + 53 =
- 23 + 25 =
- 68 + 17 =
- 97 + 62 =
- 81 + 68 =
- 82 + 62 =
- 82 + 44 =
- 47 + 17 =
- 44 + 59 =
- 53 + 96 =
- 99 + 42 =
- 75 + 12 =
- 53 + 19 =
- 15 + 90 =
- 63 + 86 =
How to do them fast
Add left to right: the tens first, then the ones, then put them together. You only ever hold one number, and the big part of the answer comes first.
47 + 38 = 85
40 + 30 = 70 → 7 + 8 = 15 → 70 + 15 = 85
When a number ends in 8 or 9, round it up and take the difference back off.
57 + 39 = 96
57 + 40 = 97 → 97 − 1 = 96
Under 2 seconds each is quick; the whole sheet in about a minute is very good. More methods are in the mental math tricks.
Answer key
- 37 + 25 = 62
- 55 + 63 = 118
- 28 + 52 = 80
- 71 + 64 = 135
- 79 + 75 = 154
- 18 + 95 = 113
- 71 + 31 = 102
- 46 + 98 = 144
- 22 + 74 = 96
- 23 + 41 = 64
- 71 + 20 = 91
- 53 + 15 = 68
- 83 + 95 = 178
- 86 + 52 = 138
- 94 + 18 = 112
- 29 + 53 = 82
- 23 + 25 = 48
- 68 + 17 = 85
- 97 + 62 = 159
- 81 + 68 = 149
- 82 + 62 = 144
- 82 + 44 = 126
- 47 + 17 = 64
- 44 + 59 = 103
- 53 + 96 = 149
- 99 + 42 = 141
- 75 + 12 = 87
- 53 + 19 = 72
- 15 + 90 = 105
- 63 + 86 = 149