Mental Subtraction Strategies

Name: _______________________________
Date: _______________________________

Strategy 1: Compensation (Adding to Make it Easier)

Add the same amount to both numbers to make an easier subtraction.

Example: 82 − 39 = ? → Think: 83 − 40 = 43

1. 74 − 29 = _____________
2. 156 − 48 = _____________
3. 93 − 57 = _____________
4. 215 − 89 = _____________

Strategy 2: Partitioning (Breaking Apart the Number)

Break the number you're subtracting into parts (tens and ones).

Example: 85 − 34 = ? → Think: 85 − 30 = 55, then 55 − 4 = 51

5. 67 − 23 = _____________
6. 142 − 56 = _____________
7. 98 − 45 = _____________
8. 184 − 72 = _____________

Strategy 3: Your Choice!

Choose the best mental strategy for each problem.

9. 125 − 68 = _____________
10. 91 − 38 = _____________
11. 176 − 54 = _____________
12. 104 − 79 = _____________
13. 230 − 95 = _____________
14. 87 − 42 = _____________

Challenge Problems 🧠

15. 512 − 298 = _____________
16. 405 − 187 = _____________