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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 355 · 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. 1.93 + 49 =
  2. 2.345 + 77 =
  3. 3.370 + 48 =
  4. 4.324 + 18 =
  5. 5.291 + 17 =
  6. 6.491 + 88 =
  7. 7.461 + 98 =
  8. 8.309 + 67 =
  9. 9.130 + 37 =
  10. 10.444 + 47 =
  11. 11.472 + 97 =
  12. 12.220 + 48 =
  13. 13.200 + 59 =
  14. 14.99 + 38 =
  15. 15.498 + 28 =
  16. 16.486 + 77 =
  17. 17.374 + 28 =
  18. 18.479 + 39 =
  19. 19.335 + 19 =
  20. 20.413 + 97 =
  21. 21.168 + 38 =
  22. 22.154 + 79 =
  23. 23.124 + 18 =
  24. 24.38 + 28 =
  25. 25.154 + 78 =
  26. 26.376 + 67 =
  27. 27.111 + 38 =
  28. 28.157 + 68 =
  29. 29.485 + 59 =
  30. 30.236 + 18 =
  31. 31.27 + 97 =
  32. 32.147 + 29 =
  33. 33.238 + 37 =
  34. 34.176 + 49 =
  35. 35.76 + 19 =
  36. 36.280 + 69 =
  37. 37.448 + 29 =
  38. 38.28 + 67 =
  39. 39.26 + 57 =
  40. 40.366 + 78 =

Answer key

  1. 142
  2. 422
  3. 418
  4. 342
  5. 308
  6. 579
  7. 559
  8. 376
  9. 167
  10. 491
  11. 569
  12. 268
  13. 259
  14. 137
  15. 526
  16. 563
  17. 402
  18. 518
  19. 354
  20. 510
  21. 206
  22. 233
  23. 142
  24. 66
  25. 232
  26. 443
  27. 149
  28. 225
  29. 544
  30. 254
  31. 124
  32. 176
  33. 275
  34. 225
  35. 95
  36. 349
  37. 477
  38. 95
  39. 83
  40. 444

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