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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 5 · 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. 1.407 + 49 =
  2. 2.440 + 67 =
  3. 3.482 + 28 =
  4. 4.233 + 18 =
  5. 5.234 + 19 =
  6. 6.350 + 97 =
  7. 7.159 + 67 =
  8. 8.42 + 68 =
  9. 9.77 + 58 =
  10. 10.169 + 28 =
  11. 11.402 + 77 =
  12. 12.113 + 28 =
  13. 13.209 + 98 =
  14. 14.121 + 37 =
  15. 15.360 + 69 =
  16. 16.219 + 68 =
  17. 17.224 + 27 =
  18. 18.55 + 58 =
  19. 19.247 + 98 =
  20. 20.107 + 77 =
  21. 21.95 + 57 =
  22. 22.453 + 59 =
  23. 23.430 + 47 =
  24. 24.434 + 78 =
  25. 25.199 + 38 =
  26. 26.186 + 97 =
  27. 27.30 + 17 =
  28. 28.41 + 29 =
  29. 29.466 + 38 =
  30. 30.48 + 68 =
  31. 31.196 + 47 =
  32. 32.59 + 17 =
  33. 33.144 + 69 =
  34. 34.250 + 77 =
  35. 35.384 + 49 =
  36. 36.416 + 59 =
  37. 37.363 + 19 =
  38. 38.458 + 47 =
  39. 39.415 + 79 =
  40. 40.347 + 88 =

Answer key

  1. 456
  2. 507
  3. 510
  4. 251
  5. 253
  6. 447
  7. 226
  8. 110
  9. 135
  10. 197
  11. 479
  12. 141
  13. 307
  14. 158
  15. 429
  16. 287
  17. 251
  18. 113
  19. 345
  20. 184
  21. 152
  22. 512
  23. 477
  24. 512
  25. 237
  26. 283
  27. 47
  28. 70
  29. 504
  30. 116
  31. 243
  32. 76
  33. 213
  34. 327
  35. 433
  36. 475
  37. 382
  38. 505
  39. 494
  40. 435

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