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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 912 · 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. 1.342 + 79 =
  2. 2.355 + 68 =
  3. 3.120 + 87 =
  4. 4.308 + 68 =
  5. 5.37 + 28 =
  6. 6.369 + 47 =
  7. 7.299 + 17 =
  8. 8.440 + 97 =
  9. 9.87 + 98 =
  10. 10.44 + 29 =
  11. 11.71 + 27 =
  12. 12.279 + 38 =
  13. 13.126 + 98 =
  14. 14.68 + 58 =
  15. 15.436 + 68 =
  16. 16.314 + 47 =
  17. 17.110 + 88 =
  18. 18.252 + 88 =
  19. 19.186 + 48 =
  20. 20.215 + 47 =
  21. 21.131 + 98 =
  22. 22.125 + 57 =
  23. 23.185 + 99 =
  24. 24.300 + 47 =
  25. 25.147 + 79 =
  26. 26.100 + 69 =
  27. 27.292 + 79 =
  28. 28.229 + 57 =
  29. 29.59 + 37 =
  30. 30.291 + 47 =
  31. 31.250 + 29 =
  32. 32.99 + 87 =
  33. 33.348 + 27 =
  34. 34.469 + 69 =
  35. 35.426 + 77 =
  36. 36.89 + 27 =
  37. 37.480 + 89 =
  38. 38.244 + 49 =
  39. 39.173 + 78 =
  40. 40.201 + 29 =

Answer key

  1. 421
  2. 423
  3. 207
  4. 376
  5. 65
  6. 416
  7. 316
  8. 537
  9. 185
  10. 73
  11. 98
  12. 317
  13. 224
  14. 126
  15. 504
  16. 361
  17. 198
  18. 340
  19. 234
  20. 262
  21. 229
  22. 182
  23. 284
  24. 347
  25. 226
  26. 169
  27. 371
  28. 286
  29. 96
  30. 338
  31. 279
  32. 186
  33. 375
  34. 538
  35. 503
  36. 116
  37. 569
  38. 293
  39. 251
  40. 230

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