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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 834 · 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. 1.446 + 28 =
  2. 2.34 + 59 =
  3. 3.345 + 17 =
  4. 4.153 + 77 =
  5. 5.400 + 59 =
  6. 6.311 + 49 =
  7. 7.441 + 79 =
  8. 8.225 + 69 =
  9. 9.495 + 99 =
  10. 10.37 + 79 =
  11. 11.278 + 89 =
  12. 12.487 + 88 =
  13. 13.373 + 28 =
  14. 14.91 + 29 =
  15. 15.402 + 17 =
  16. 16.51 + 88 =
  17. 17.58 + 97 =
  18. 18.45 + 39 =
  19. 19.62 + 27 =
  20. 20.441 + 38 =
  21. 21.351 + 19 =
  22. 22.458 + 79 =
  23. 23.216 + 39 =
  24. 24.193 + 28 =
  25. 25.370 + 27 =
  26. 26.441 + 48 =
  27. 27.287 + 18 =
  28. 28.296 + 49 =
  29. 29.191 + 29 =
  30. 30.448 + 77 =
  31. 31.328 + 78 =
  32. 32.406 + 49 =
  33. 33.112 + 37 =
  34. 34.104 + 27 =
  35. 35.440 + 47 =
  36. 36.60 + 57 =
  37. 37.209 + 19 =
  38. 38.73 + 98 =
  39. 39.295 + 29 =
  40. 40.61 + 18 =

Answer key

  1. 474
  2. 93
  3. 362
  4. 230
  5. 459
  6. 360
  7. 520
  8. 294
  9. 594
  10. 116
  11. 367
  12. 575
  13. 401
  14. 120
  15. 419
  16. 139
  17. 155
  18. 84
  19. 89
  20. 479
  21. 370
  22. 537
  23. 255
  24. 221
  25. 397
  26. 489
  27. 305
  28. 345
  29. 220
  30. 525
  31. 406
  32. 455
  33. 149
  34. 131
  35. 487
  36. 117
  37. 228
  38. 171
  39. 324
  40. 79

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