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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 505 · 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. 1.41 + 67 =
  2. 2.405 + 39 =
  3. 3.234 + 58 =
  4. 4.217 + 59 =
  5. 5.132 + 69 =
  6. 6.175 + 47 =
  7. 7.53 + 87 =
  8. 8.317 + 38 =
  9. 9.463 + 78 =
  10. 10.81 + 89 =
  11. 11.198 + 59 =
  12. 12.333 + 38 =
  13. 13.285 + 28 =
  14. 14.426 + 57 =
  15. 15.405 + 19 =
  16. 16.330 + 29 =
  17. 17.397 + 88 =
  18. 18.191 + 77 =
  19. 19.41 + 18 =
  20. 20.338 + 88 =
  21. 21.175 + 88 =
  22. 22.333 + 77 =
  23. 23.323 + 58 =
  24. 24.273 + 27 =
  25. 25.99 + 59 =
  26. 26.315 + 48 =
  27. 27.160 + 39 =
  28. 28.436 + 49 =
  29. 29.42 + 97 =
  30. 30.96 + 68 =
  31. 31.315 + 29 =
  32. 32.415 + 47 =
  33. 33.415 + 89 =
  34. 34.171 + 97 =
  35. 35.404 + 18 =
  36. 36.65 + 37 =
  37. 37.384 + 57 =
  38. 38.229 + 49 =
  39. 39.459 + 57 =
  40. 40.390 + 47 =

Answer key

  1. 108
  2. 444
  3. 292
  4. 276
  5. 201
  6. 222
  7. 140
  8. 355
  9. 541
  10. 170
  11. 257
  12. 371
  13. 313
  14. 483
  15. 424
  16. 359
  17. 485
  18. 268
  19. 59
  20. 426
  21. 263
  22. 410
  23. 381
  24. 300
  25. 158
  26. 363
  27. 199
  28. 485
  29. 139
  30. 164
  31. 344
  32. 462
  33. 504
  34. 268
  35. 422
  36. 102
  37. 441
  38. 278
  39. 516
  40. 437

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