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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 524 · 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. 1.329 + 99 =
  2. 2.219 + 29 =
  3. 3.249 + 18 =
  4. 4.294 + 39 =
  5. 5.319 + 28 =
  6. 6.401 + 47 =
  7. 7.348 + 57 =
  8. 8.85 + 37 =
  9. 9.279 + 88 =
  10. 10.63 + 18 =
  11. 11.186 + 58 =
  12. 12.135 + 57 =
  13. 13.261 + 27 =
  14. 14.139 + 68 =
  15. 15.399 + 58 =
  16. 16.32 + 78 =
  17. 17.177 + 47 =
  18. 18.116 + 99 =
  19. 19.244 + 57 =
  20. 20.72 + 69 =
  21. 21.101 + 28 =
  22. 22.322 + 68 =
  23. 23.52 + 37 =
  24. 24.266 + 28 =
  25. 25.342 + 97 =
  26. 26.90 + 17 =
  27. 27.409 + 98 =
  28. 28.46 + 78 =
  29. 29.58 + 19 =
  30. 30.420 + 57 =
  31. 31.86 + 39 =
  32. 32.329 + 17 =
  33. 33.411 + 98 =
  34. 34.232 + 68 =
  35. 35.294 + 69 =
  36. 36.110 + 48 =
  37. 37.80 + 88 =
  38. 38.356 + 39 =
  39. 39.467 + 87 =
  40. 40.405 + 49 =

Answer key

  1. 428
  2. 248
  3. 267
  4. 333
  5. 347
  6. 448
  7. 405
  8. 122
  9. 367
  10. 81
  11. 244
  12. 192
  13. 288
  14. 207
  15. 457
  16. 110
  17. 224
  18. 215
  19. 301
  20. 141
  21. 129
  22. 390
  23. 89
  24. 294
  25. 439
  26. 107
  27. 507
  28. 124
  29. 77
  30. 477
  31. 125
  32. 346
  33. 509
  34. 300
  35. 363
  36. 158
  37. 168
  38. 395
  39. 554
  40. 454

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