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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 429 · 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. 1.331 + 47 =
  2. 2.154 + 78 =
  3. 3.334 + 87 =
  4. 4.231 + 89 =
  5. 5.227 + 57 =
  6. 6.123 + 17 =
  7. 7.52 + 69 =
  8. 8.274 + 19 =
  9. 9.290 + 57 =
  10. 10.41 + 58 =
  11. 11.60 + 48 =
  12. 12.369 + 39 =
  13. 13.97 + 68 =
  14. 14.135 + 27 =
  15. 15.479 + 27 =
  16. 16.472 + 47 =
  17. 17.160 + 19 =
  18. 18.52 + 67 =
  19. 19.56 + 47 =
  20. 20.305 + 19 =
  21. 21.87 + 48 =
  22. 22.81 + 77 =
  23. 23.183 + 37 =
  24. 24.194 + 48 =
  25. 25.70 + 19 =
  26. 26.467 + 78 =
  27. 27.67 + 27 =
  28. 28.52 + 19 =
  29. 29.349 + 88 =
  30. 30.104 + 69 =
  31. 31.225 + 89 =
  32. 32.291 + 87 =
  33. 33.355 + 78 =
  34. 34.215 + 29 =
  35. 35.306 + 89 =
  36. 36.435 + 78 =
  37. 37.60 + 97 =
  38. 38.487 + 37 =
  39. 39.449 + 78 =
  40. 40.87 + 19 =

Answer key

  1. 378
  2. 232
  3. 421
  4. 320
  5. 284
  6. 140
  7. 121
  8. 293
  9. 347
  10. 99
  11. 108
  12. 408
  13. 165
  14. 162
  15. 506
  16. 519
  17. 179
  18. 119
  19. 103
  20. 324
  21. 135
  22. 158
  23. 220
  24. 242
  25. 89
  26. 545
  27. 94
  28. 71
  29. 437
  30. 173
  31. 314
  32. 378
  33. 433
  34. 244
  35. 395
  36. 513
  37. 157
  38. 524
  39. 527
  40. 106

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