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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 305 · 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. 1.431 + 49 =
  2. 2.156 + 27 =
  3. 3.357 + 89 =
  4. 4.303 + 87 =
  5. 5.84 + 78 =
  6. 6.29 + 29 =
  7. 7.200 + 39 =
  8. 8.426 + 28 =
  9. 9.486 + 18 =
  10. 10.480 + 47 =
  11. 11.56 + 27 =
  12. 12.180 + 38 =
  13. 13.429 + 39 =
  14. 14.59 + 87 =
  15. 15.498 + 28 =
  16. 16.437 + 57 =
  17. 17.256 + 18 =
  18. 18.417 + 17 =
  19. 19.454 + 59 =
  20. 20.348 + 79 =
  21. 21.240 + 37 =
  22. 22.266 + 47 =
  23. 23.451 + 58 =
  24. 24.147 + 38 =
  25. 25.40 + 67 =
  26. 26.121 + 57 =
  27. 27.50 + 68 =
  28. 28.191 + 37 =
  29. 29.32 + 28 =
  30. 30.302 + 28 =
  31. 31.233 + 37 =
  32. 32.302 + 17 =
  33. 33.482 + 99 =
  34. 34.395 + 98 =
  35. 35.64 + 68 =
  36. 36.497 + 59 =
  37. 37.480 + 99 =
  38. 38.256 + 77 =
  39. 39.456 + 17 =
  40. 40.331 + 19 =

Answer key

  1. 480
  2. 183
  3. 446
  4. 390
  5. 162
  6. 58
  7. 239
  8. 454
  9. 504
  10. 527
  11. 83
  12. 218
  13. 468
  14. 146
  15. 526
  16. 494
  17. 274
  18. 434
  19. 513
  20. 427
  21. 277
  22. 313
  23. 509
  24. 185
  25. 107
  26. 178
  27. 118
  28. 228
  29. 60
  30. 330
  31. 270
  32. 319
  33. 581
  34. 493
  35. 132
  36. 556
  37. 579
  38. 333
  39. 473
  40. 350

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