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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 638 · 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. 1.123 + 27 =
  2. 2.160 + 59 =
  3. 3.365 + 69 =
  4. 4.241 + 37 =
  5. 5.251 + 39 =
  6. 6.344 + 38 =
  7. 7.310 + 18 =
  8. 8.56 + 98 =
  9. 9.435 + 48 =
  10. 10.326 + 17 =
  11. 11.401 + 28 =
  12. 12.213 + 37 =
  13. 13.365 + 49 =
  14. 14.348 + 29 =
  15. 15.182 + 67 =
  16. 16.390 + 97 =
  17. 17.388 + 78 =
  18. 18.226 + 27 =
  19. 19.292 + 99 =
  20. 20.289 + 48 =
  21. 21.219 + 78 =
  22. 22.339 + 69 =
  23. 23.82 + 99 =
  24. 24.424 + 37 =
  25. 25.420 + 58 =
  26. 26.294 + 59 =
  27. 27.107 + 29 =
  28. 28.99 + 79 =
  29. 29.339 + 38 =
  30. 30.78 + 18 =
  31. 31.426 + 77 =
  32. 32.406 + 47 =
  33. 33.261 + 27 =
  34. 34.164 + 59 =
  35. 35.300 + 87 =
  36. 36.63 + 99 =
  37. 37.277 + 47 =
  38. 38.287 + 89 =
  39. 39.423 + 89 =
  40. 40.123 + 59 =

Answer key

  1. 150
  2. 219
  3. 434
  4. 278
  5. 290
  6. 382
  7. 328
  8. 154
  9. 483
  10. 343
  11. 429
  12. 250
  13. 414
  14. 377
  15. 249
  16. 487
  17. 466
  18. 253
  19. 391
  20. 337
  21. 297
  22. 408
  23. 181
  24. 461
  25. 478
  26. 353
  27. 136
  28. 178
  29. 377
  30. 96
  31. 503
  32. 453
  33. 288
  34. 223
  35. 387
  36. 162
  37. 324
  38. 376
  39. 512
  40. 182

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