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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 399 · 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. 1.391 + 19 =
  2. 2.123 + 29 =
  3. 3.127 + 17 =
  4. 4.429 + 39 =
  5. 5.94 + 89 =
  6. 6.396 + 38 =
  7. 7.223 + 87 =
  8. 8.421 + 17 =
  9. 9.242 + 88 =
  10. 10.121 + 98 =
  11. 11.420 + 68 =
  12. 12.466 + 18 =
  13. 13.172 + 79 =
  14. 14.240 + 19 =
  15. 15.401 + 27 =
  16. 16.94 + 87 =
  17. 17.295 + 59 =
  18. 18.191 + 17 =
  19. 19.167 + 37 =
  20. 20.67 + 68 =
  21. 21.395 + 58 =
  22. 22.263 + 48 =
  23. 23.413 + 19 =
  24. 24.132 + 57 =
  25. 25.105 + 77 =
  26. 26.374 + 18 =
  27. 27.360 + 97 =
  28. 28.160 + 17 =
  29. 29.244 + 49 =
  30. 30.318 + 68 =
  31. 31.230 + 88 =
  32. 32.438 + 47 =
  33. 33.379 + 39 =
  34. 34.344 + 59 =
  35. 35.399 + 37 =
  36. 36.467 + 58 =
  37. 37.194 + 38 =
  38. 38.62 + 39 =
  39. 39.270 + 78 =
  40. 40.321 + 79 =

Answer key

  1. 410
  2. 152
  3. 144
  4. 468
  5. 183
  6. 434
  7. 310
  8. 438
  9. 330
  10. 219
  11. 488
  12. 484
  13. 251
  14. 259
  15. 428
  16. 181
  17. 354
  18. 208
  19. 204
  20. 135
  21. 453
  22. 311
  23. 432
  24. 189
  25. 182
  26. 392
  27. 457
  28. 177
  29. 293
  30. 386
  31. 318
  32. 485
  33. 418
  34. 403
  35. 436
  36. 525
  37. 232
  38. 101
  39. 348
  40. 400

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