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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 48 · 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. 1.30 + 78 =
  2. 2.397 + 78 =
  3. 3.339 + 39 =
  4. 4.96 + 99 =
  5. 5.92 + 89 =
  6. 6.270 + 77 =
  7. 7.266 + 59 =
  8. 8.110 + 27 =
  9. 9.317 + 69 =
  10. 10.90 + 99 =
  11. 11.333 + 67 =
  12. 12.423 + 29 =
  13. 13.179 + 98 =
  14. 14.301 + 18 =
  15. 15.143 + 98 =
  16. 16.113 + 69 =
  17. 17.426 + 47 =
  18. 18.489 + 17 =
  19. 19.495 + 48 =
  20. 20.196 + 99 =
  21. 21.98 + 18 =
  22. 22.210 + 89 =
  23. 23.123 + 79 =
  24. 24.337 + 49 =
  25. 25.422 + 19 =
  26. 26.146 + 47 =
  27. 27.400 + 87 =
  28. 28.268 + 99 =
  29. 29.71 + 88 =
  30. 30.58 + 87 =
  31. 31.118 + 97 =
  32. 32.71 + 47 =
  33. 33.248 + 77 =
  34. 34.481 + 97 =
  35. 35.141 + 17 =
  36. 36.272 + 49 =
  37. 37.197 + 88 =
  38. 38.115 + 29 =
  39. 39.404 + 98 =
  40. 40.163 + 18 =

Answer key

  1. 108
  2. 475
  3. 378
  4. 195
  5. 181
  6. 347
  7. 325
  8. 137
  9. 386
  10. 189
  11. 400
  12. 452
  13. 277
  14. 319
  15. 241
  16. 182
  17. 473
  18. 506
  19. 543
  20. 295
  21. 116
  22. 299
  23. 202
  24. 386
  25. 441
  26. 193
  27. 487
  28. 367
  29. 159
  30. 145
  31. 215
  32. 118
  33. 325
  34. 578
  35. 158
  36. 321
  37. 285
  38. 144
  39. 502
  40. 181

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