Two-Digit Addition & Subtraction — Answer Key
Part A: Sort the Words
Sort each word or number into the correct category box.
1. Sort each addition problem into the correct category.
Needs Regrouping
35 + 4748 + 2519 + 44 No Regrouping
21 + 3653 + 1432 + 51 Regrouping is needed when the ones digits cannot be subtracted or when their sum is 10 or more. Problems like 56 + 38 (6 + 8 = 14) need regrouping, while 76 − 34 (6 − 4 = 2) does not.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. 76 − 34 = 42.
Subtract the ones: 6 − 4 = 2. Subtract the tens: 7 − 3 = 4. So 76 − 34 = 42.
2. 90 − 53 = 37.
Regroup: borrow 1 ten so 0 ones becomes 10 ones. 10 − 3 = 7. Then 8 − 5 = 3. So 90 − 53 = 37.
3. 64 − 36 = 28.
To find the missing number, subtract: 64 − 28 = 36. Check: 64 − 36 = 28.
4. 85 − 41 = 44.
Subtract the ones: 5 − 1 = 4. Subtract the tens: 8 − 4 = 4. So 85 − 41 = 44.
5. 65 − 15 = 50.
To find the missing number, add: 50 + 15 = 65. Check: 65 − 15 = 50.
Part C: True or False?
Read each statement. Circle True or False.
1. 56 + 38 = 94.
True False
Add the ones: 6 + 8 = 14, write 4 and carry 1. Add the tens: 5 + 3 + 1 = 9. So 56 + 38 = 94.
2. 73 − 45 = 38.
True False
73 − 45 = 28, not 38. Regroup: 13 − 5 = 8 in the ones place, then 6 − 4 = 2 in the tens place.
3. 29 + 41 = 70.
True False
Add the ones: 9 + 1 = 10, write 0 and carry 1. Add the tens: 2 + 4 + 1 = 7. So 29 + 41 = 70.
4. 80 − 36 = 54.
True False
80 − 36 = 44, not 54. Regroup: 10 − 6 = 4 in the ones place, then 7 − 3 = 4 in the tens place.