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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 445 · 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. 1.240 + 47 =
  2. 2.75 + 78 =
  3. 3.120 + 19 =
  4. 4.245 + 68 =
  5. 5.347 + 18 =
  6. 6.425 + 47 =
  7. 7.97 + 29 =
  8. 8.171 + 17 =
  9. 9.40 + 39 =
  10. 10.282 + 18 =
  11. 11.352 + 28 =
  12. 12.44 + 88 =
  13. 13.395 + 68 =
  14. 14.407 + 47 =
  15. 15.372 + 67 =
  16. 16.465 + 17 =
  17. 17.123 + 98 =
  18. 18.243 + 87 =
  19. 19.366 + 58 =
  20. 20.71 + 79 =
  21. 21.186 + 78 =
  22. 22.88 + 77 =
  23. 23.360 + 69 =
  24. 24.314 + 79 =
  25. 25.88 + 17 =
  26. 26.159 + 37 =
  27. 27.285 + 48 =
  28. 28.100 + 39 =
  29. 29.116 + 59 =
  30. 30.89 + 28 =
  31. 31.481 + 47 =
  32. 32.214 + 37 =
  33. 33.227 + 68 =
  34. 34.388 + 38 =
  35. 35.107 + 48 =
  36. 36.57 + 89 =
  37. 37.434 + 27 =
  38. 38.112 + 87 =
  39. 39.260 + 49 =
  40. 40.277 + 57 =

Answer key

  1. 287
  2. 153
  3. 139
  4. 313
  5. 365
  6. 472
  7. 126
  8. 188
  9. 79
  10. 300
  11. 380
  12. 132
  13. 463
  14. 454
  15. 439
  16. 482
  17. 221
  18. 330
  19. 424
  20. 150
  21. 264
  22. 165
  23. 429
  24. 393
  25. 105
  26. 196
  27. 333
  28. 139
  29. 175
  30. 117
  31. 528
  32. 251
  33. 295
  34. 426
  35. 155
  36. 146
  37. 461
  38. 199
  39. 309
  40. 334

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