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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 407 · 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. 1.431 + 57 =
  2. 2.151 + 67 =
  3. 3.483 + 88 =
  4. 4.324 + 18 =
  5. 5.110 + 17 =
  6. 6.249 + 79 =
  7. 7.93 + 27 =
  8. 8.75 + 47 =
  9. 9.429 + 29 =
  10. 10.296 + 39 =
  11. 11.104 + 67 =
  12. 12.494 + 57 =
  13. 13.337 + 27 =
  14. 14.154 + 69 =
  15. 15.210 + 48 =
  16. 16.56 + 97 =
  17. 17.288 + 77 =
  18. 18.73 + 58 =
  19. 19.26 + 99 =
  20. 20.361 + 48 =
  21. 21.471 + 69 =
  22. 22.364 + 17 =
  23. 23.401 + 17 =
  24. 24.401 + 37 =
  25. 25.292 + 49 =
  26. 26.293 + 38 =
  27. 27.87 + 47 =
  28. 28.455 + 38 =
  29. 29.254 + 47 =
  30. 30.52 + 38 =
  31. 31.332 + 69 =
  32. 32.334 + 39 =
  33. 33.196 + 99 =
  34. 34.283 + 47 =
  35. 35.229 + 19 =
  36. 36.448 + 39 =
  37. 37.376 + 27 =
  38. 38.266 + 37 =
  39. 39.470 + 69 =
  40. 40.267 + 79 =

Answer key

  1. 488
  2. 218
  3. 571
  4. 342
  5. 127
  6. 328
  7. 120
  8. 122
  9. 458
  10. 335
  11. 171
  12. 551
  13. 364
  14. 223
  15. 258
  16. 153
  17. 365
  18. 131
  19. 125
  20. 409
  21. 540
  22. 381
  23. 418
  24. 438
  25. 341
  26. 331
  27. 134
  28. 493
  29. 301
  30. 90
  31. 401
  32. 373
  33. 295
  34. 330
  35. 248
  36. 487
  37. 403
  38. 303
  39. 539
  40. 346

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