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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 372 · 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. 1.44 + 18 =
  2. 2.455 + 47 =
  3. 3.451 + 69 =
  4. 4.161 + 48 =
  5. 5.247 + 27 =
  6. 6.76 + 68 =
  7. 7.338 + 59 =
  8. 8.88 + 48 =
  9. 9.78 + 37 =
  10. 10.144 + 97 =
  11. 11.224 + 78 =
  12. 12.143 + 57 =
  13. 13.255 + 29 =
  14. 14.97 + 57 =
  15. 15.226 + 69 =
  16. 16.378 + 19 =
  17. 17.265 + 88 =
  18. 18.449 + 89 =
  19. 19.44 + 79 =
  20. 20.50 + 18 =
  21. 21.163 + 97 =
  22. 22.265 + 37 =
  23. 23.453 + 58 =
  24. 24.443 + 79 =
  25. 25.300 + 69 =
  26. 26.450 + 27 =
  27. 27.442 + 68 =
  28. 28.306 + 88 =
  29. 29.206 + 39 =
  30. 30.276 + 17 =
  31. 31.159 + 37 =
  32. 32.145 + 87 =
  33. 33.467 + 18 =
  34. 34.307 + 77 =
  35. 35.44 + 67 =
  36. 36.85 + 47 =
  37. 37.484 + 27 =
  38. 38.118 + 47 =
  39. 39.135 + 97 =
  40. 40.25 + 19 =

Answer key

  1. 62
  2. 502
  3. 520
  4. 209
  5. 274
  6. 144
  7. 397
  8. 136
  9. 115
  10. 241
  11. 302
  12. 200
  13. 284
  14. 154
  15. 295
  16. 397
  17. 353
  18. 538
  19. 123
  20. 68
  21. 260
  22. 302
  23. 511
  24. 522
  25. 369
  26. 477
  27. 510
  28. 394
  29. 245
  30. 293
  31. 196
  32. 232
  33. 485
  34. 384
  35. 111
  36. 132
  37. 511
  38. 165
  39. 232
  40. 44

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