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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 172 · 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. 1.430 + 29 =
  2. 2.106 + 17 =
  3. 3.42 + 38 =
  4. 4.257 + 49 =
  5. 5.59 + 57 =
  6. 6.47 + 17 =
  7. 7.400 + 69 =
  8. 8.392 + 68 =
  9. 9.335 + 17 =
  10. 10.120 + 19 =
  11. 11.187 + 39 =
  12. 12.171 + 49 =
  13. 13.337 + 87 =
  14. 14.45 + 67 =
  15. 15.250 + 37 =
  16. 16.88 + 49 =
  17. 17.438 + 39 =
  18. 18.86 + 57 =
  19. 19.474 + 48 =
  20. 20.193 + 67 =
  21. 21.51 + 57 =
  22. 22.133 + 79 =
  23. 23.346 + 39 =
  24. 24.156 + 78 =
  25. 25.399 + 99 =
  26. 26.437 + 79 =
  27. 27.422 + 29 =
  28. 28.111 + 59 =
  29. 29.158 + 19 =
  30. 30.402 + 37 =
  31. 31.249 + 57 =
  32. 32.56 + 88 =
  33. 33.217 + 47 =
  34. 34.363 + 28 =
  35. 35.151 + 49 =
  36. 36.207 + 59 =
  37. 37.42 + 79 =
  38. 38.80 + 78 =
  39. 39.309 + 69 =
  40. 40.105 + 28 =

Answer key

  1. 459
  2. 123
  3. 80
  4. 306
  5. 116
  6. 64
  7. 469
  8. 460
  9. 352
  10. 139
  11. 226
  12. 220
  13. 424
  14. 112
  15. 287
  16. 137
  17. 477
  18. 143
  19. 522
  20. 260
  21. 108
  22. 212
  23. 385
  24. 234
  25. 498
  26. 516
  27. 451
  28. 170
  29. 177
  30. 439
  31. 306
  32. 144
  33. 264
  34. 391
  35. 200
  36. 266
  37. 121
  38. 158
  39. 378
  40. 133

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