FreeMath
Grade 3medium

Mental Math Addition Strategies Practice

Practice mental math addition strategies for third grade. Use make-ten, doubles, friendly numbers, and break-apart strategies for quick mental calculations.

Loading...

All 20 Practice Problems

Every question in this set. Solve them on paper, or use the interactive tool above for instant feedback and hints.

  1. 1.Use make-10: 8 + 5 = ?
  2. 2.Use make-10: 9 + 7 = ?
  3. 3.Add by tens: 34 + 20 = ?
  4. 4.Add by tens: 56 + 30 = ?
  5. 5.Use doubles: 7 + 8 = ?
  6. 6.Use doubles: 6 + 7 = ?
  7. 7.Friendly numbers: 99 + 45 = ?
  8. 8.Friendly numbers: 98 + 37 = ?
  9. 9.Add left to right: 45 + 32 = ?
  10. 10.Add left to right: 67 + 21 = ?
  11. 11.Break apart: 47 + 25 = 47 + 20 + 5 = ?
  12. 12.Break apart: 38 + 46 = 38 + 40 + 6 = ?
  13. 13.Compensation: 49 + 35 = 50 + 34 = ?
  14. 14.Compensation: 28 + 47 = 30 + 45 = ?
  15. 15.Use make-10: 7 + 6 = ?
  16. 16.Add by tens: 78 + 40 = ?
  17. 17.Friendly numbers: 199 + 56 = ?
  18. 18.Add left to right: 53 + 44 = ?
  19. 19.Break apart: 56 + 37 = ?
  20. 20.Compensation: 39 + 52 = 40 + 51 = ?
Show answer key
  1. 1.Use make-10: 8 + 5 = ? Answer: 13
  2. 2.Use make-10: 9 + 7 = ? Answer: 16
  3. 3.Add by tens: 34 + 20 = ? Answer: 54
  4. 4.Add by tens: 56 + 30 = ? Answer: 86
  5. 5.Use doubles: 7 + 8 = ? Answer: 15
  6. 6.Use doubles: 6 + 7 = ? Answer: 13
  7. 7.Friendly numbers: 99 + 45 = ? Answer: 144
  8. 8.Friendly numbers: 98 + 37 = ? Answer: 135
  9. 9.Add left to right: 45 + 32 = ? Answer: 77
  10. 10.Add left to right: 67 + 21 = ? Answer: 88
  11. 11.Break apart: 47 + 25 = 47 + 20 + 5 = ? Answer: 72
  12. 12.Break apart: 38 + 46 = 38 + 40 + 6 = ? Answer: 84
  13. 13.Compensation: 49 + 35 = 50 + 34 = ? Answer: 84
  14. 14.Compensation: 28 + 47 = 30 + 45 = ? Answer: 75
  15. 15.Use make-10: 7 + 6 = ? Answer: 13
  16. 16.Add by tens: 78 + 40 = ? Answer: 118
  17. 17.Friendly numbers: 199 + 56 = ? Answer: 255
  18. 18.Add left to right: 53 + 44 = ? Answer: 97
  19. 19.Break apart: 56 + 37 = ? Answer: 93
  20. 20.Compensation: 39 + 52 = 40 + 51 = ? Answer: 91

About This Practice

This practice set includes 20 mental math problems. These strategies help calculate without paper and pencil.

Want more practice? See all Grade 3 practice →