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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 3 · 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. 1.53 + 47 =
  2. 2.469 + 27 =
  3. 3.145 + 68 =
  4. 4.262 + 27 =
  5. 5.390 + 39 =
  6. 6.58 + 58 =
  7. 7.480 + 87 =
  8. 8.29 + 59 =
  9. 9.112 + 19 =
  10. 10.153 + 68 =
  11. 11.245 + 39 =
  12. 12.251 + 78 =
  13. 13.150 + 19 =
  14. 14.299 + 68 =
  15. 15.334 + 79 =
  16. 16.335 + 78 =
  17. 17.159 + 89 =
  18. 18.313 + 99 =
  19. 19.31 + 68 =
  20. 20.409 + 28 =
  21. 21.199 + 77 =
  22. 22.263 + 39 =
  23. 23.72 + 67 =
  24. 24.353 + 19 =
  25. 25.80 + 97 =
  26. 26.77 + 69 =
  27. 27.385 + 58 =
  28. 28.346 + 79 =
  29. 29.41 + 68 =
  30. 30.322 + 17 =
  31. 31.475 + 18 =
  32. 32.40 + 57 =
  33. 33.412 + 77 =
  34. 34.340 + 99 =
  35. 35.487 + 38 =
  36. 36.48 + 69 =
  37. 37.365 + 87 =
  38. 38.193 + 88 =
  39. 39.310 + 89 =
  40. 40.204 + 29 =

Answer key

  1. 100
  2. 496
  3. 213
  4. 289
  5. 429
  6. 116
  7. 567
  8. 88
  9. 131
  10. 221
  11. 284
  12. 329
  13. 169
  14. 367
  15. 413
  16. 413
  17. 248
  18. 412
  19. 99
  20. 437
  21. 276
  22. 302
  23. 139
  24. 372
  25. 177
  26. 146
  27. 443
  28. 425
  29. 109
  30. 339
  31. 493
  32. 97
  33. 489
  34. 439
  35. 525
  36. 117
  37. 452
  38. 281
  39. 399
  40. 233

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