Two-Digit Addition & Subtraction — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. What is 56 + 37?
A) 83
B) 93
C) 82
D) 92
Add the ones: 6 + 7 = 13, write 3 and carry 1. Add the tens: 5 + 3 + 1 = 9. So 56 + 37 = 93.
2. When you subtract 74 − 48, what do you need to do first?
A) Subtract the tens first
B) Regroup 1 ten as 10 ones
C) Add the ones digits
D) Borrow from the hundreds
Since 4 ones is less than 8 ones, you cannot subtract the ones directly. You need to regroup 1 ten as 10 ones first, making 14 − 8 = 6 in the ones place.
3. Which problem does NOT need regrouping?
A) 45 + 38
B) 62 + 21
C) 57 + 26
D) 39 + 43
62 + 21 does not need regrouping because 2 + 1 = 3 in the ones place, which is less than 10. No carrying is needed.
4. What is 80 − 35?
A) 55
B) 45
C) 35
D) 65
Regroup: 10 − 5 = 5 in the ones place, then 7 − 3 = 4 in the tens place. So 80 − 35 = 45.
Part B: Fill in the Blank
Write the correct answer on each line.
1. 67 + 25 = 92.
Add the ones: 7 + 5 = 12, write 2 and carry 1. Add the tens: 6 + 2 + 1 = 9. So 67 + 25 = 92.
2. 83 − 46 = 37.
Regroup: 13 − 6 = 7 in the ones place, then 7 − 4 = 3 in the tens place. So 83 − 46 = 37.
3. 39 + 48 = 87.
Add the ones: 9 + 8 = 17, write 7 and carry 1. Add the tens: 3 + 4 + 1 = 8. So 39 + 48 = 87.
4. 72 − 55 = 17.
Regroup: 12 − 5 = 7 in the ones place, then 6 − 5 = 1 in the tens place. So 72 − 55 = 17.
5. 54 + 29 = 83.
Add the ones: 4 + 9 = 13, write 3 and carry 1. Add the tens: 5 + 2 + 1 = 8. So 54 + 29 = 83.