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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 836 · 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. 1.443 + 49 =
  2. 2.385 + 68 =
  3. 3.472 + 77 =
  4. 4.57 + 88 =
  5. 5.52 + 87 =
  6. 6.310 + 38 =
  7. 7.186 + 17 =
  8. 8.114 + 27 =
  9. 9.373 + 19 =
  10. 10.377 + 57 =
  11. 11.46 + 97 =
  12. 12.121 + 27 =
  13. 13.451 + 18 =
  14. 14.246 + 17 =
  15. 15.43 + 67 =
  16. 16.74 + 18 =
  17. 17.187 + 47 =
  18. 18.100 + 57 =
  19. 19.228 + 17 =
  20. 20.295 + 17 =
  21. 21.363 + 49 =
  22. 22.425 + 29 =
  23. 23.476 + 69 =
  24. 24.401 + 87 =
  25. 25.74 + 49 =
  26. 26.72 + 38 =
  27. 27.181 + 99 =
  28. 28.434 + 79 =
  29. 29.29 + 29 =
  30. 30.477 + 19 =
  31. 31.381 + 67 =
  32. 32.426 + 17 =
  33. 33.160 + 29 =
  34. 34.277 + 47 =
  35. 35.204 + 28 =
  36. 36.259 + 69 =
  37. 37.109 + 17 =
  38. 38.157 + 47 =
  39. 39.56 + 28 =
  40. 40.188 + 29 =

Answer key

  1. 492
  2. 453
  3. 549
  4. 145
  5. 139
  6. 348
  7. 203
  8. 141
  9. 392
  10. 434
  11. 143
  12. 148
  13. 469
  14. 263
  15. 110
  16. 92
  17. 234
  18. 157
  19. 245
  20. 312
  21. 412
  22. 454
  23. 545
  24. 488
  25. 123
  26. 110
  27. 280
  28. 513
  29. 58
  30. 496
  31. 448
  32. 443
  33. 189
  34. 324
  35. 232
  36. 328
  37. 126
  38. 204
  39. 84
  40. 217

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