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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 649 · 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. 1.401 + 17 =
  2. 2.329 + 77 =
  3. 3.100 + 77 =
  4. 4.248 + 88 =
  5. 5.191 + 57 =
  6. 6.491 + 57 =
  7. 7.189 + 39 =
  8. 8.386 + 29 =
  9. 9.181 + 47 =
  10. 10.375 + 17 =
  11. 11.426 + 79 =
  12. 12.28 + 38 =
  13. 13.328 + 29 =
  14. 14.303 + 27 =
  15. 15.36 + 38 =
  16. 16.466 + 28 =
  17. 17.357 + 67 =
  18. 18.194 + 29 =
  19. 19.173 + 48 =
  20. 20.157 + 57 =
  21. 21.56 + 57 =
  22. 22.152 + 47 =
  23. 23.94 + 77 =
  24. 24.346 + 29 =
  25. 25.419 + 98 =
  26. 26.462 + 98 =
  27. 27.66 + 47 =
  28. 28.457 + 19 =
  29. 29.75 + 69 =
  30. 30.426 + 18 =
  31. 31.272 + 57 =
  32. 32.79 + 67 =
  33. 33.255 + 79 =
  34. 34.438 + 89 =
  35. 35.339 + 98 =
  36. 36.50 + 57 =
  37. 37.493 + 57 =
  38. 38.86 + 28 =
  39. 39.273 + 88 =
  40. 40.377 + 59 =

Answer key

  1. 418
  2. 406
  3. 177
  4. 336
  5. 248
  6. 548
  7. 228
  8. 415
  9. 228
  10. 392
  11. 505
  12. 66
  13. 357
  14. 330
  15. 74
  16. 494
  17. 424
  18. 223
  19. 221
  20. 214
  21. 113
  22. 199
  23. 171
  24. 375
  25. 517
  26. 560
  27. 113
  28. 476
  29. 144
  30. 444
  31. 329
  32. 146
  33. 334
  34. 527
  35. 437
  36. 107
  37. 550
  38. 114
  39. 361
  40. 436

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