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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 568 · 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. 1.123 + 28 =
  2. 2.57 + 79 =
  3. 3.350 + 27 =
  4. 4.47 + 19 =
  5. 5.120 + 39 =
  6. 6.257 + 28 =
  7. 7.26 + 67 =
  8. 8.279 + 78 =
  9. 9.189 + 99 =
  10. 10.288 + 68 =
  11. 11.81 + 18 =
  12. 12.379 + 28 =
  13. 13.220 + 38 =
  14. 14.36 + 19 =
  15. 15.111 + 59 =
  16. 16.46 + 68 =
  17. 17.153 + 68 =
  18. 18.419 + 17 =
  19. 19.414 + 57 =
  20. 20.81 + 17 =
  21. 21.299 + 19 =
  22. 22.65 + 57 =
  23. 23.397 + 59 =
  24. 24.398 + 88 =
  25. 25.141 + 57 =
  26. 26.238 + 47 =
  27. 27.461 + 38 =
  28. 28.249 + 47 =
  29. 29.197 + 47 =
  30. 30.248 + 97 =
  31. 31.312 + 48 =
  32. 32.355 + 57 =
  33. 33.301 + 99 =
  34. 34.69 + 17 =
  35. 35.161 + 17 =
  36. 36.147 + 19 =
  37. 37.311 + 59 =
  38. 38.294 + 18 =
  39. 39.249 + 89 =
  40. 40.377 + 78 =

Answer key

  1. 151
  2. 136
  3. 377
  4. 66
  5. 159
  6. 285
  7. 93
  8. 357
  9. 288
  10. 356
  11. 99
  12. 407
  13. 258
  14. 55
  15. 170
  16. 114
  17. 221
  18. 436
  19. 471
  20. 98
  21. 318
  22. 122
  23. 456
  24. 486
  25. 198
  26. 285
  27. 499
  28. 296
  29. 244
  30. 345
  31. 360
  32. 412
  33. 400
  34. 86
  35. 178
  36. 166
  37. 370
  38. 312
  39. 338
  40. 455

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