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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 51 · 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. 1.104 + 57 =
  2. 2.307 + 97 =
  3. 3.101 + 97 =
  4. 4.234 + 58 =
  5. 5.77 + 47 =
  6. 6.210 + 47 =
  7. 7.253 + 77 =
  8. 8.385 + 69 =
  9. 9.297 + 68 =
  10. 10.79 + 37 =
  11. 11.328 + 68 =
  12. 12.346 + 67 =
  13. 13.359 + 18 =
  14. 14.430 + 97 =
  15. 15.191 + 29 =
  16. 16.358 + 88 =
  17. 17.390 + 48 =
  18. 18.261 + 18 =
  19. 19.221 + 87 =
  20. 20.30 + 39 =
  21. 21.320 + 59 =
  22. 22.182 + 48 =
  23. 23.58 + 77 =
  24. 24.299 + 48 =
  25. 25.50 + 59 =
  26. 26.421 + 77 =
  27. 27.107 + 17 =
  28. 28.61 + 79 =
  29. 29.67 + 49 =
  30. 30.318 + 78 =
  31. 31.235 + 77 =
  32. 32.342 + 37 =
  33. 33.253 + 88 =
  34. 34.462 + 87 =
  35. 35.327 + 18 =
  36. 36.360 + 68 =
  37. 37.207 + 47 =
  38. 38.357 + 27 =
  39. 39.317 + 79 =
  40. 40.335 + 27 =

Answer key

  1. 161
  2. 404
  3. 198
  4. 292
  5. 124
  6. 257
  7. 330
  8. 454
  9. 365
  10. 116
  11. 396
  12. 413
  13. 377
  14. 527
  15. 220
  16. 446
  17. 438
  18. 279
  19. 308
  20. 69
  21. 379
  22. 230
  23. 135
  24. 347
  25. 109
  26. 498
  27. 124
  28. 140
  29. 116
  30. 396
  31. 312
  32. 379
  33. 341
  34. 549
  35. 345
  36. 428
  37. 254
  38. 384
  39. 396
  40. 362

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