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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 457 · 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. 1.102 + 49 =
  2. 2.67 + 78 =
  3. 3.280 + 18 =
  4. 4.120 + 87 =
  5. 5.458 + 19 =
  6. 6.238 + 39 =
  7. 7.385 + 78 =
  8. 8.239 + 47 =
  9. 9.497 + 78 =
  10. 10.193 + 18 =
  11. 11.55 + 78 =
  12. 12.75 + 37 =
  13. 13.217 + 79 =
  14. 14.211 + 37 =
  15. 15.66 + 68 =
  16. 16.159 + 68 =
  17. 17.93 + 79 =
  18. 18.349 + 39 =
  19. 19.245 + 18 =
  20. 20.100 + 88 =
  21. 21.124 + 87 =
  22. 22.365 + 97 =
  23. 23.329 + 78 =
  24. 24.477 + 98 =
  25. 25.465 + 58 =
  26. 26.410 + 29 =
  27. 27.164 + 68 =
  28. 28.278 + 17 =
  29. 29.304 + 28 =
  30. 30.220 + 57 =
  31. 31.156 + 97 =
  32. 32.290 + 98 =
  33. 33.59 + 39 =
  34. 34.325 + 28 =
  35. 35.383 + 79 =
  36. 36.254 + 78 =
  37. 37.234 + 39 =
  38. 38.379 + 38 =
  39. 39.468 + 39 =
  40. 40.311 + 59 =

Answer key

  1. 151
  2. 145
  3. 298
  4. 207
  5. 477
  6. 277
  7. 463
  8. 286
  9. 575
  10. 211
  11. 133
  12. 112
  13. 296
  14. 248
  15. 134
  16. 227
  17. 172
  18. 388
  19. 263
  20. 188
  21. 211
  22. 462
  23. 407
  24. 575
  25. 523
  26. 439
  27. 232
  28. 295
  29. 332
  30. 277
  31. 253
  32. 388
  33. 98
  34. 353
  35. 462
  36. 332
  37. 273
  38. 417
  39. 507
  40. 370

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