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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 163 · 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. 1.372 + 37 =
  2. 2.279 + 88 =
  3. 3.323 + 59 =
  4. 4.390 + 68 =
  5. 5.452 + 77 =
  6. 6.432 + 79 =
  7. 7.468 + 19 =
  8. 8.444 + 99 =
  9. 9.141 + 77 =
  10. 10.280 + 37 =
  11. 11.270 + 78 =
  12. 12.245 + 37 =
  13. 13.130 + 88 =
  14. 14.102 + 68 =
  15. 15.48 + 17 =
  16. 16.196 + 97 =
  17. 17.258 + 77 =
  18. 18.121 + 49 =
  19. 19.471 + 38 =
  20. 20.79 + 88 =
  21. 21.65 + 98 =
  22. 22.391 + 49 =
  23. 23.314 + 28 =
  24. 24.262 + 27 =
  25. 25.374 + 29 =
  26. 26.34 + 67 =
  27. 27.289 + 28 =
  28. 28.30 + 17 =
  29. 29.165 + 88 =
  30. 30.48 + 87 =
  31. 31.273 + 88 =
  32. 32.280 + 89 =
  33. 33.361 + 19 =
  34. 34.78 + 99 =
  35. 35.349 + 88 =
  36. 36.118 + 28 =
  37. 37.86 + 77 =
  38. 38.333 + 89 =
  39. 39.434 + 49 =
  40. 40.394 + 79 =

Answer key

  1. 409
  2. 367
  3. 382
  4. 458
  5. 529
  6. 511
  7. 487
  8. 543
  9. 218
  10. 317
  11. 348
  12. 282
  13. 218
  14. 170
  15. 65
  16. 293
  17. 335
  18. 170
  19. 509
  20. 167
  21. 163
  22. 440
  23. 342
  24. 289
  25. 403
  26. 101
  27. 317
  28. 47
  29. 253
  30. 135
  31. 361
  32. 369
  33. 380
  34. 177
  35. 437
  36. 146
  37. 163
  38. 422
  39. 483
  40. 473

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