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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 950 · 40 questions
TalentJR

The fast method (Round up, then fix): Round the number ending in 7, 8 or 9 up to the next ten: 39 → 40. Add the round number. Take away the extra you added (here 1).

NameDateTime takenScore ___ / 40
  1. 1.432 + 77 =
  2. 2.282 + 28 =
  3. 3.315 + 39 =
  4. 4.168 + 49 =
  5. 5.139 + 47 =
  6. 6.400 + 29 =
  7. 7.334 + 57 =
  8. 8.489 + 87 =
  9. 9.25 + 27 =
  10. 10.447 + 79 =
  11. 11.232 + 78 =
  12. 12.296 + 19 =
  13. 13.255 + 19 =
  14. 14.494 + 58 =
  15. 15.430 + 69 =
  16. 16.152 + 57 =
  17. 17.106 + 97 =
  18. 18.218 + 28 =
  19. 19.328 + 28 =
  20. 20.404 + 97 =
  21. 21.224 + 69 =
  22. 22.58 + 38 =
  23. 23.362 + 98 =
  24. 24.207 + 17 =
  25. 25.34 + 89 =
  26. 26.136 + 69 =
  27. 27.28 + 47 =
  28. 28.160 + 68 =
  29. 29.345 + 39 =
  30. 30.48 + 39 =
  31. 31.28 + 78 =
  32. 32.256 + 27 =
  33. 33.482 + 98 =
  34. 34.144 + 39 =
  35. 35.143 + 99 =
  36. 36.493 + 28 =
  37. 37.160 + 17 =
  38. 38.412 + 37 =
  39. 39.103 + 87 =
  40. 40.348 + 57 =

Answer key

  1. 509
  2. 310
  3. 354
  4. 217
  5. 186
  6. 429
  7. 391
  8. 576
  9. 52
  10. 526
  11. 310
  12. 315
  13. 274
  14. 552
  15. 499
  16. 209
  17. 203
  18. 246
  19. 356
  20. 501
  21. 293
  22. 96
  23. 460
  24. 224
  25. 123
  26. 205
  27. 75
  28. 228
  29. 384
  30. 87
  31. 106
  32. 283
  33. 580
  34. 183
  35. 242
  36. 521
  37. 177
  38. 449
  39. 190
  40. 405

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