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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 366 · 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. 1.162 + 59 =
  2. 2.402 + 19 =
  3. 3.338 + 98 =
  4. 4.492 + 68 =
  5. 5.313 + 39 =
  6. 6.104 + 69 =
  7. 7.145 + 98 =
  8. 8.145 + 39 =
  9. 9.201 + 78 =
  10. 10.67 + 98 =
  11. 11.345 + 19 =
  12. 12.107 + 17 =
  13. 13.253 + 57 =
  14. 14.27 + 79 =
  15. 15.249 + 58 =
  16. 16.304 + 27 =
  17. 17.59 + 58 =
  18. 18.173 + 29 =
  19. 19.85 + 47 =
  20. 20.483 + 69 =
  21. 21.222 + 18 =
  22. 22.229 + 18 =
  23. 23.289 + 27 =
  24. 24.120 + 39 =
  25. 25.155 + 79 =
  26. 26.136 + 37 =
  27. 27.374 + 19 =
  28. 28.125 + 17 =
  29. 29.485 + 19 =
  30. 30.275 + 19 =
  31. 31.207 + 38 =
  32. 32.485 + 78 =
  33. 33.484 + 77 =
  34. 34.45 + 99 =
  35. 35.258 + 19 =
  36. 36.216 + 47 =
  37. 37.176 + 78 =
  38. 38.361 + 39 =
  39. 39.152 + 68 =
  40. 40.338 + 77 =

Answer key

  1. 221
  2. 421
  3. 436
  4. 560
  5. 352
  6. 173
  7. 243
  8. 184
  9. 279
  10. 165
  11. 364
  12. 124
  13. 310
  14. 106
  15. 307
  16. 331
  17. 117
  18. 202
  19. 132
  20. 552
  21. 240
  22. 247
  23. 316
  24. 159
  25. 234
  26. 173
  27. 393
  28. 142
  29. 504
  30. 294
  31. 245
  32. 563
  33. 561
  34. 144
  35. 277
  36. 263
  37. 254
  38. 400
  39. 220
  40. 415

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