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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 320 · 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. 1.456 + 37 =
  2. 2.182 + 48 =
  3. 3.258 + 37 =
  4. 4.382 + 98 =
  5. 5.324 + 77 =
  6. 6.455 + 49 =
  7. 7.179 + 97 =
  8. 8.130 + 99 =
  9. 9.360 + 68 =
  10. 10.240 + 67 =
  11. 11.35 + 17 =
  12. 12.431 + 79 =
  13. 13.207 + 19 =
  14. 14.303 + 59 =
  15. 15.117 + 18 =
  16. 16.395 + 57 =
  17. 17.295 + 69 =
  18. 18.224 + 77 =
  19. 19.112 + 79 =
  20. 20.274 + 49 =
  21. 21.29 + 68 =
  22. 22.26 + 47 =
  23. 23.262 + 37 =
  24. 24.320 + 28 =
  25. 25.48 + 18 =
  26. 26.333 + 87 =
  27. 27.199 + 68 =
  28. 28.63 + 39 =
  29. 29.157 + 29 =
  30. 30.164 + 87 =
  31. 31.443 + 67 =
  32. 32.374 + 28 =
  33. 33.440 + 58 =
  34. 34.35 + 58 =
  35. 35.254 + 89 =
  36. 36.477 + 38 =
  37. 37.373 + 38 =
  38. 38.216 + 47 =
  39. 39.112 + 37 =
  40. 40.106 + 77 =

Answer key

  1. 493
  2. 230
  3. 295
  4. 480
  5. 401
  6. 504
  7. 276
  8. 229
  9. 428
  10. 307
  11. 52
  12. 510
  13. 226
  14. 362
  15. 135
  16. 452
  17. 364
  18. 301
  19. 191
  20. 323
  21. 97
  22. 73
  23. 299
  24. 348
  25. 66
  26. 420
  27. 267
  28. 102
  29. 186
  30. 251
  31. 510
  32. 402
  33. 498
  34. 93
  35. 343
  36. 515
  37. 411
  38. 263
  39. 149
  40. 183

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