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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 401 · 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. 1.131 + 28 =
  2. 2.454 + 97 =
  3. 3.472 + 29 =
  4. 4.387 + 48 =
  5. 5.100 + 98 =
  6. 6.374 + 88 =
  7. 7.224 + 67 =
  8. 8.41 + 57 =
  9. 9.333 + 57 =
  10. 10.69 + 28 =
  11. 11.177 + 18 =
  12. 12.417 + 68 =
  13. 13.44 + 99 =
  14. 14.306 + 27 =
  15. 15.120 + 57 =
  16. 16.119 + 98 =
  17. 17.41 + 79 =
  18. 18.351 + 57 =
  19. 19.159 + 87 =
  20. 20.321 + 38 =
  21. 21.129 + 57 =
  22. 22.276 + 38 =
  23. 23.172 + 58 =
  24. 24.411 + 19 =
  25. 25.81 + 67 =
  26. 26.191 + 17 =
  27. 27.119 + 37 =
  28. 28.284 + 77 =
  29. 29.106 + 78 =
  30. 30.476 + 48 =
  31. 31.487 + 18 =
  32. 32.365 + 18 =
  33. 33.165 + 79 =
  34. 34.258 + 47 =
  35. 35.431 + 59 =
  36. 36.115 + 89 =
  37. 37.117 + 17 =
  38. 38.135 + 67 =
  39. 39.50 + 88 =
  40. 40.310 + 27 =

Answer key

  1. 159
  2. 551
  3. 501
  4. 435
  5. 198
  6. 462
  7. 291
  8. 98
  9. 390
  10. 97
  11. 195
  12. 485
  13. 143
  14. 333
  15. 177
  16. 217
  17. 120
  18. 408
  19. 246
  20. 359
  21. 186
  22. 314
  23. 230
  24. 430
  25. 148
  26. 208
  27. 156
  28. 361
  29. 184
  30. 524
  31. 505
  32. 383
  33. 244
  34. 305
  35. 490
  36. 204
  37. 134
  38. 202
  39. 138
  40. 337

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