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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 578 · 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. 1.303 + 98 =
  2. 2.412 + 59 =
  3. 3.59 + 89 =
  4. 4.443 + 29 =
  5. 5.54 + 48 =
  6. 6.71 + 98 =
  7. 7.483 + 97 =
  8. 8.321 + 99 =
  9. 9.481 + 29 =
  10. 10.181 + 27 =
  11. 11.431 + 27 =
  12. 12.135 + 89 =
  13. 13.204 + 28 =
  14. 14.29 + 89 =
  15. 15.83 + 37 =
  16. 16.87 + 37 =
  17. 17.493 + 87 =
  18. 18.44 + 28 =
  19. 19.59 + 37 =
  20. 20.486 + 67 =
  21. 21.384 + 37 =
  22. 22.287 + 88 =
  23. 23.248 + 87 =
  24. 24.288 + 29 =
  25. 25.422 + 47 =
  26. 26.335 + 87 =
  27. 27.46 + 59 =
  28. 28.151 + 47 =
  29. 29.77 + 38 =
  30. 30.185 + 18 =
  31. 31.380 + 89 =
  32. 32.284 + 79 =
  33. 33.301 + 77 =
  34. 34.227 + 79 =
  35. 35.160 + 19 =
  36. 36.216 + 48 =
  37. 37.277 + 19 =
  38. 38.406 + 78 =
  39. 39.28 + 38 =
  40. 40.499 + 38 =

Answer key

  1. 401
  2. 471
  3. 148
  4. 472
  5. 102
  6. 169
  7. 580
  8. 420
  9. 510
  10. 208
  11. 458
  12. 224
  13. 232
  14. 118
  15. 120
  16. 124
  17. 580
  18. 72
  19. 96
  20. 553
  21. 421
  22. 375
  23. 335
  24. 317
  25. 469
  26. 422
  27. 105
  28. 198
  29. 115
  30. 203
  31. 469
  32. 363
  33. 378
  34. 306
  35. 179
  36. 264
  37. 296
  38. 484
  39. 66
  40. 537

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