Two-Digit Addition & Subtraction — Answer Key
Part A: Sort the Words
Sort each word or number into the correct category box.
1. Sort each problem: needs regrouping or no regrouping.
No Regrouping
54+2361+1452+41 Needs Regrouping
37+4643+3976+18 Add the ones digits first to decide. Sums of 9 or less (4+3, 1+4, 2+1) stay in the ones place with no regrouping. Sums of 10 or more (7+6, 3+9, 6+8) require carrying 1 ten over.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. 26 + 47 = 73.
Add the ones: 6 + 7 = 13, write 3 and carry 1. Add the tens: 2 + 4 + 1 = 7. So 26 + 47 = 73.
2. 58 + 34 = 92.
Add the ones: 8 + 4 = 12, write 2 and carry 1. Add the tens: 5 + 3 + 1 = 9. So 58 + 34 = 92.
3. 33 + 39 = 72.
To find the missing addend, subtract: 72 − 39 = 33. Check: 33 + 39 = 72.
4. 45 + 28 = 73.
Add the ones: 5 + 8 = 13, write 3 and carry 1. Add the tens: 4 + 2 + 1 = 7. So 45 + 28 = 73.
5. 67 + 24 = 91.
To find the missing addend, subtract: 91 − 67 = 24. Check: 67 + 24 = 91.
Part C: True or False?
Read each statement. Circle True or False.
1. 43 + 38 = 81.
True False
Add the ones: 3 + 8 = 11, write 1 and carry 1. Add the tens: 4 + 3 + 1 = 8. The sum 81 matches the equation.
2. 92 - 57 = 45.
True False
Regroup: 12 − 7 = 5 in the ones, then 8 − 5 = 3 in the tens. The real answer is 35, not 45.
3. 65 - 29 = 36.
True False
Regroup: 15 − 9 = 6 in the ones, then 5 − 2 = 3 in the tens. The result is 36, so this is true.
4. 28 + 53 = 71.
True False
Add the ones: 8 + 3 = 11, write 1 and carry 1. Add the tens: 2 + 5 + 1 = 8. The correct sum is 81, not 71.