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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 46 · 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. 1.442 + 37 =
  2. 2.406 + 69 =
  3. 3.365 + 89 =
  4. 4.343 + 37 =
  5. 5.373 + 99 =
  6. 6.165 + 98 =
  7. 7.272 + 69 =
  8. 8.315 + 17 =
  9. 9.465 + 39 =
  10. 10.249 + 99 =
  11. 11.73 + 27 =
  12. 12.258 + 99 =
  13. 13.357 + 88 =
  14. 14.183 + 47 =
  15. 15.29 + 28 =
  16. 16.330 + 89 =
  17. 17.150 + 78 =
  18. 18.423 + 87 =
  19. 19.123 + 57 =
  20. 20.163 + 37 =
  21. 21.231 + 37 =
  22. 22.416 + 27 =
  23. 23.339 + 39 =
  24. 24.266 + 27 =
  25. 25.257 + 58 =
  26. 26.178 + 99 =
  27. 27.131 + 98 =
  28. 28.231 + 49 =
  29. 29.60 + 99 =
  30. 30.161 + 38 =
  31. 31.451 + 58 =
  32. 32.408 + 58 =
  33. 33.426 + 77 =
  34. 34.422 + 17 =
  35. 35.185 + 28 =
  36. 36.405 + 37 =
  37. 37.57 + 29 =
  38. 38.215 + 99 =
  39. 39.432 + 78 =
  40. 40.416 + 37 =

Answer key

  1. 479
  2. 475
  3. 454
  4. 380
  5. 472
  6. 263
  7. 341
  8. 332
  9. 504
  10. 348
  11. 100
  12. 357
  13. 445
  14. 230
  15. 57
  16. 419
  17. 228
  18. 510
  19. 180
  20. 200
  21. 268
  22. 443
  23. 378
  24. 293
  25. 315
  26. 277
  27. 229
  28. 280
  29. 159
  30. 199
  31. 509
  32. 466
  33. 503
  34. 439
  35. 213
  36. 442
  37. 86
  38. 314
  39. 510
  40. 453

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