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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 278 · 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. 1.350 + 29 =
  2. 2.442 + 67 =
  3. 3.96 + 47 =
  4. 4.280 + 78 =
  5. 5.497 + 58 =
  6. 6.479 + 37 =
  7. 7.444 + 58 =
  8. 8.381 + 27 =
  9. 9.423 + 47 =
  10. 10.340 + 69 =
  11. 11.374 + 39 =
  12. 12.242 + 98 =
  13. 13.411 + 18 =
  14. 14.199 + 87 =
  15. 15.416 + 17 =
  16. 16.493 + 49 =
  17. 17.206 + 38 =
  18. 18.489 + 18 =
  19. 19.149 + 67 =
  20. 20.202 + 79 =
  21. 21.238 + 97 =
  22. 22.422 + 17 =
  23. 23.439 + 97 =
  24. 24.451 + 17 =
  25. 25.204 + 67 =
  26. 26.464 + 37 =
  27. 27.146 + 57 =
  28. 28.56 + 69 =
  29. 29.442 + 37 =
  30. 30.273 + 99 =
  31. 31.182 + 99 =
  32. 32.319 + 19 =
  33. 33.52 + 88 =
  34. 34.84 + 87 =
  35. 35.156 + 58 =
  36. 36.353 + 69 =
  37. 37.134 + 28 =
  38. 38.209 + 18 =
  39. 39.202 + 68 =
  40. 40.249 + 98 =

Answer key

  1. 379
  2. 509
  3. 143
  4. 358
  5. 555
  6. 516
  7. 502
  8. 408
  9. 470
  10. 409
  11. 413
  12. 340
  13. 429
  14. 286
  15. 433
  16. 542
  17. 244
  18. 507
  19. 216
  20. 281
  21. 335
  22. 439
  23. 536
  24. 468
  25. 271
  26. 501
  27. 203
  28. 125
  29. 479
  30. 372
  31. 281
  32. 338
  33. 140
  34. 171
  35. 214
  36. 422
  37. 162
  38. 227
  39. 270
  40. 347

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