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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 521 · 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. 1.77 + 38 =
  2. 2.485 + 78 =
  3. 3.419 + 38 =
  4. 4.111 + 57 =
  5. 5.91 + 48 =
  6. 6.462 + 87 =
  7. 7.467 + 19 =
  8. 8.264 + 79 =
  9. 9.316 + 27 =
  10. 10.49 + 37 =
  11. 11.49 + 99 =
  12. 12.211 + 27 =
  13. 13.89 + 87 =
  14. 14.223 + 48 =
  15. 15.48 + 79 =
  16. 16.462 + 58 =
  17. 17.466 + 58 =
  18. 18.179 + 97 =
  19. 19.452 + 47 =
  20. 20.222 + 68 =
  21. 21.451 + 37 =
  22. 22.52 + 58 =
  23. 23.262 + 57 =
  24. 24.444 + 59 =
  25. 25.371 + 78 =
  26. 26.148 + 79 =
  27. 27.129 + 59 =
  28. 28.388 + 17 =
  29. 29.339 + 38 =
  30. 30.61 + 77 =
  31. 31.231 + 88 =
  32. 32.74 + 39 =
  33. 33.491 + 59 =
  34. 34.259 + 38 =
  35. 35.479 + 59 =
  36. 36.383 + 27 =
  37. 37.35 + 29 =
  38. 38.452 + 37 =
  39. 39.96 + 47 =
  40. 40.391 + 79 =

Answer key

  1. 115
  2. 563
  3. 457
  4. 168
  5. 139
  6. 549
  7. 486
  8. 343
  9. 343
  10. 86
  11. 148
  12. 238
  13. 176
  14. 271
  15. 127
  16. 520
  17. 524
  18. 276
  19. 499
  20. 290
  21. 488
  22. 110
  23. 319
  24. 503
  25. 449
  26. 227
  27. 188
  28. 405
  29. 377
  30. 138
  31. 319
  32. 113
  33. 550
  34. 297
  35. 538
  36. 410
  37. 64
  38. 489
  39. 143
  40. 470

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