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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 50 · 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. 1.443 + 37 =
  2. 2.320 + 37 =
  3. 3.124 + 27 =
  4. 4.392 + 28 =
  5. 5.460 + 79 =
  6. 6.305 + 67 =
  7. 7.39 + 28 =
  8. 8.100 + 29 =
  9. 9.296 + 49 =
  10. 10.163 + 28 =
  11. 11.227 + 27 =
  12. 12.356 + 37 =
  13. 13.144 + 68 =
  14. 14.338 + 79 =
  15. 15.65 + 57 =
  16. 16.51 + 97 =
  17. 17.149 + 49 =
  18. 18.55 + 99 =
  19. 19.38 + 38 =
  20. 20.182 + 47 =
  21. 21.181 + 57 =
  22. 22.334 + 59 =
  23. 23.225 + 39 =
  24. 24.161 + 98 =
  25. 25.374 + 39 =
  26. 26.218 + 17 =
  27. 27.199 + 59 =
  28. 28.202 + 27 =
  29. 29.375 + 69 =
  30. 30.206 + 49 =
  31. 31.422 + 88 =
  32. 32.270 + 18 =
  33. 33.314 + 67 =
  34. 34.489 + 79 =
  35. 35.303 + 97 =
  36. 36.236 + 87 =
  37. 37.242 + 27 =
  38. 38.201 + 19 =
  39. 39.426 + 17 =
  40. 40.307 + 59 =

Answer key

  1. 480
  2. 357
  3. 151
  4. 420
  5. 539
  6. 372
  7. 67
  8. 129
  9. 345
  10. 191
  11. 254
  12. 393
  13. 212
  14. 417
  15. 122
  16. 148
  17. 198
  18. 154
  19. 76
  20. 229
  21. 238
  22. 393
  23. 264
  24. 259
  25. 413
  26. 235
  27. 258
  28. 229
  29. 444
  30. 255
  31. 510
  32. 288
  33. 381
  34. 568
  35. 400
  36. 323
  37. 269
  38. 220
  39. 443
  40. 366

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