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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 146 · 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. 1.288 + 39 =
  2. 2.248 + 97 =
  3. 3.38 + 39 =
  4. 4.488 + 57 =
  5. 5.190 + 38 =
  6. 6.95 + 79 =
  7. 7.316 + 58 =
  8. 8.91 + 38 =
  9. 9.117 + 88 =
  10. 10.389 + 68 =
  11. 11.230 + 77 =
  12. 12.485 + 98 =
  13. 13.151 + 97 =
  14. 14.402 + 67 =
  15. 15.405 + 69 =
  16. 16.340 + 57 =
  17. 17.413 + 27 =
  18. 18.481 + 19 =
  19. 19.285 + 98 =
  20. 20.265 + 79 =
  21. 21.323 + 97 =
  22. 22.90 + 97 =
  23. 23.76 + 77 =
  24. 24.174 + 59 =
  25. 25.292 + 28 =
  26. 26.139 + 37 =
  27. 27.264 + 49 =
  28. 28.423 + 59 =
  29. 29.455 + 49 =
  30. 30.233 + 18 =
  31. 31.369 + 57 =
  32. 32.270 + 38 =
  33. 33.144 + 99 =
  34. 34.244 + 88 =
  35. 35.152 + 79 =
  36. 36.430 + 49 =
  37. 37.370 + 48 =
  38. 38.116 + 18 =
  39. 39.367 + 77 =
  40. 40.305 + 67 =

Answer key

  1. 327
  2. 345
  3. 77
  4. 545
  5. 228
  6. 174
  7. 374
  8. 129
  9. 205
  10. 457
  11. 307
  12. 583
  13. 248
  14. 469
  15. 474
  16. 397
  17. 440
  18. 500
  19. 383
  20. 344
  21. 420
  22. 187
  23. 153
  24. 233
  25. 320
  26. 176
  27. 313
  28. 482
  29. 504
  30. 251
  31. 426
  32. 308
  33. 243
  34. 332
  35. 231
  36. 479
  37. 418
  38. 134
  39. 444
  40. 372

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