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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 45 · 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. 1.102 + 37 =
  2. 2.313 + 18 =
  3. 3.213 + 97 =
  4. 4.50 + 67 =
  5. 5.223 + 48 =
  6. 6.398 + 87 =
  7. 7.266 + 98 =
  8. 8.278 + 77 =
  9. 9.326 + 17 =
  10. 10.377 + 47 =
  11. 11.259 + 38 =
  12. 12.321 + 77 =
  13. 13.30 + 77 =
  14. 14.384 + 89 =
  15. 15.152 + 48 =
  16. 16.170 + 39 =
  17. 17.231 + 87 =
  18. 18.339 + 87 =
  19. 19.41 + 19 =
  20. 20.499 + 68 =
  21. 21.355 + 97 =
  22. 22.382 + 29 =
  23. 23.58 + 57 =
  24. 24.387 + 99 =
  25. 25.478 + 39 =
  26. 26.84 + 69 =
  27. 27.145 + 37 =
  28. 28.126 + 47 =
  29. 29.433 + 77 =
  30. 30.290 + 87 =
  31. 31.336 + 49 =
  32. 32.464 + 49 =
  33. 33.59 + 87 =
  34. 34.162 + 58 =
  35. 35.281 + 59 =
  36. 36.107 + 47 =
  37. 37.271 + 48 =
  38. 38.248 + 69 =
  39. 39.453 + 59 =
  40. 40.420 + 79 =

Answer key

  1. 139
  2. 331
  3. 310
  4. 117
  5. 271
  6. 485
  7. 364
  8. 355
  9. 343
  10. 424
  11. 297
  12. 398
  13. 107
  14. 473
  15. 200
  16. 209
  17. 318
  18. 426
  19. 60
  20. 567
  21. 452
  22. 411
  23. 115
  24. 486
  25. 517
  26. 153
  27. 182
  28. 173
  29. 510
  30. 377
  31. 385
  32. 513
  33. 146
  34. 220
  35. 340
  36. 154
  37. 319
  38. 317
  39. 512
  40. 499

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