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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 370 · 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. 1.155 + 17 =
  2. 2.392 + 87 =
  3. 3.441 + 49 =
  4. 4.134 + 69 =
  5. 5.218 + 89 =
  6. 6.352 + 59 =
  7. 7.362 + 18 =
  8. 8.328 + 18 =
  9. 9.411 + 18 =
  10. 10.364 + 37 =
  11. 11.250 + 28 =
  12. 12.148 + 18 =
  13. 13.416 + 57 =
  14. 14.254 + 47 =
  15. 15.428 + 89 =
  16. 16.463 + 49 =
  17. 17.135 + 88 =
  18. 18.182 + 67 =
  19. 19.160 + 97 =
  20. 20.317 + 28 =
  21. 21.180 + 49 =
  22. 22.34 + 79 =
  23. 23.75 + 99 =
  24. 24.57 + 68 =
  25. 25.100 + 38 =
  26. 26.296 + 28 =
  27. 27.402 + 48 =
  28. 28.346 + 47 =
  29. 29.270 + 37 =
  30. 30.207 + 88 =
  31. 31.268 + 68 =
  32. 32.192 + 68 =
  33. 33.490 + 68 =
  34. 34.384 + 67 =
  35. 35.483 + 87 =
  36. 36.153 + 37 =
  37. 37.187 + 39 =
  38. 38.143 + 37 =
  39. 39.344 + 19 =
  40. 40.95 + 57 =

Answer key

  1. 172
  2. 479
  3. 490
  4. 203
  5. 307
  6. 411
  7. 380
  8. 346
  9. 429
  10. 401
  11. 278
  12. 166
  13. 473
  14. 301
  15. 517
  16. 512
  17. 223
  18. 249
  19. 257
  20. 345
  21. 229
  22. 113
  23. 174
  24. 125
  25. 138
  26. 324
  27. 450
  28. 393
  29. 307
  30. 295
  31. 336
  32. 260
  33. 558
  34. 451
  35. 570
  36. 190
  37. 226
  38. 180
  39. 363
  40. 152

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