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Add by Rounding Worksheet

Speed calculation lesson 2: Add by rounding · Set 379 · 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. 1.43 + 57 =
  2. 2.304 + 99 =
  3. 3.87 + 59 =
  4. 4.350 + 47 =
  5. 5.263 + 17 =
  6. 6.499 + 17 =
  7. 7.163 + 98 =
  8. 8.345 + 17 =
  9. 9.100 + 48 =
  10. 10.458 + 68 =
  11. 11.322 + 67 =
  12. 12.355 + 18 =
  13. 13.48 + 67 =
  14. 14.43 + 28 =
  15. 15.310 + 97 =
  16. 16.65 + 79 =
  17. 17.262 + 28 =
  18. 18.181 + 49 =
  19. 19.413 + 77 =
  20. 20.90 + 79 =
  21. 21.135 + 57 =
  22. 22.76 + 89 =
  23. 23.366 + 48 =
  24. 24.93 + 67 =
  25. 25.229 + 38 =
  26. 26.270 + 27 =
  27. 27.64 + 19 =
  28. 28.419 + 17 =
  29. 29.300 + 39 =
  30. 30.133 + 37 =
  31. 31.445 + 78 =
  32. 32.459 + 48 =
  33. 33.228 + 17 =
  34. 34.69 + 17 =
  35. 35.93 + 17 =
  36. 36.155 + 37 =
  37. 37.301 + 89 =
  38. 38.29 + 58 =
  39. 39.480 + 29 =
  40. 40.68 + 98 =

Answer key

  1. 100
  2. 403
  3. 146
  4. 397
  5. 280
  6. 516
  7. 261
  8. 362
  9. 148
  10. 526
  11. 389
  12. 373
  13. 115
  14. 71
  15. 407
  16. 144
  17. 290
  18. 230
  19. 490
  20. 169
  21. 192
  22. 165
  23. 414
  24. 160
  25. 267
  26. 297
  27. 83
  28. 436
  29. 339
  30. 170
  31. 523
  32. 507
  33. 245
  34. 86
  35. 110
  36. 192
  37. 390
  38. 87
  39. 509
  40. 166

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