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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 828 · 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. 1.470 + 99 =
  2. 2.490 + 39 =
  3. 3.90 + 89 =
  4. 4.290 + 27 =
  5. 5.27 + 38 =
  6. 6.116 + 99 =
  7. 7.339 + 28 =
  8. 8.432 + 37 =
  9. 9.170 + 39 =
  10. 10.228 + 17 =
  11. 11.387 + 29 =
  12. 12.25 + 48 =
  13. 13.418 + 39 =
  14. 14.463 + 38 =
  15. 15.229 + 58 =
  16. 16.276 + 98 =
  17. 17.214 + 57 =
  18. 18.29 + 69 =
  19. 19.102 + 58 =
  20. 20.151 + 27 =
  21. 21.129 + 98 =
  22. 22.369 + 29 =
  23. 23.472 + 28 =
  24. 24.142 + 67 =
  25. 25.304 + 19 =
  26. 26.119 + 27 =
  27. 27.476 + 69 =
  28. 28.86 + 59 =
  29. 29.205 + 28 =
  30. 30.284 + 88 =
  31. 31.324 + 79 =
  32. 32.271 + 59 =
  33. 33.271 + 38 =
  34. 34.57 + 37 =
  35. 35.191 + 48 =
  36. 36.393 + 37 =
  37. 37.317 + 78 =
  38. 38.453 + 17 =
  39. 39.455 + 67 =
  40. 40.327 + 17 =

Answer key

  1. 569
  2. 529
  3. 179
  4. 317
  5. 65
  6. 215
  7. 367
  8. 469
  9. 209
  10. 245
  11. 416
  12. 73
  13. 457
  14. 501
  15. 287
  16. 374
  17. 271
  18. 98
  19. 160
  20. 178
  21. 227
  22. 398
  23. 500
  24. 209
  25. 323
  26. 146
  27. 545
  28. 145
  29. 233
  30. 372
  31. 403
  32. 330
  33. 309
  34. 94
  35. 239
  36. 430
  37. 395
  38. 470
  39. 522
  40. 344

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