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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 490 · 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. 1.126 + 18 =
  2. 2.91 + 38 =
  3. 3.284 + 87 =
  4. 4.301 + 47 =
  5. 5.135 + 89 =
  6. 6.418 + 18 =
  7. 7.65 + 87 =
  8. 8.273 + 39 =
  9. 9.400 + 87 =
  10. 10.281 + 68 =
  11. 11.337 + 17 =
  12. 12.124 + 59 =
  13. 13.153 + 27 =
  14. 14.238 + 58 =
  15. 15.40 + 67 =
  16. 16.218 + 99 =
  17. 17.447 + 27 =
  18. 18.467 + 59 =
  19. 19.489 + 29 =
  20. 20.476 + 17 =
  21. 21.217 + 87 =
  22. 22.360 + 17 =
  23. 23.403 + 69 =
  24. 24.195 + 47 =
  25. 25.70 + 79 =
  26. 26.251 + 19 =
  27. 27.215 + 19 =
  28. 28.58 + 87 =
  29. 29.449 + 98 =
  30. 30.215 + 19 =
  31. 31.496 + 77 =
  32. 32.460 + 98 =
  33. 33.395 + 78 =
  34. 34.482 + 47 =
  35. 35.91 + 17 =
  36. 36.264 + 57 =
  37. 37.229 + 29 =
  38. 38.487 + 39 =
  39. 39.47 + 79 =
  40. 40.194 + 97 =

Answer key

  1. 144
  2. 129
  3. 371
  4. 348
  5. 224
  6. 436
  7. 152
  8. 312
  9. 487
  10. 349
  11. 354
  12. 183
  13. 180
  14. 296
  15. 107
  16. 317
  17. 474
  18. 526
  19. 518
  20. 493
  21. 304
  22. 377
  23. 472
  24. 242
  25. 149
  26. 270
  27. 234
  28. 145
  29. 547
  30. 234
  31. 573
  32. 558
  33. 473
  34. 529
  35. 108
  36. 321
  37. 258
  38. 526
  39. 126
  40. 291

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