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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 951 · 40 questions
TalentJR

The trick (Pairs): Pair the first and last numbers: each pair adds to n + 1. Count the pairs — or multiply n × (n + 1) and halve it. Odd numbers 1 + 3 + 5 + …: count them and multiply that count by itself.

NameDateTime takenScore ___ / 40
  1. 1.1 + 2 + 3 + … + 54 =
  2. 2.1 + 2 + 3 + … + 52 =
  3. 3.1 + 2 + 3 + … + 88 =
  4. 4.1 + 3 + 5 + … + 41 =
  5. 5.1 + 2 + 3 + … + 15 =
  6. 6.1 + 3 + 5 + … + 37 =
  7. 7.1 + 2 + 3 + … + 11 =
  8. 8.1 + 2 + 3 + … + 49 =
  9. 9.1 + 3 + 5 + … + 13 =
  10. 10.1 + 2 + 3 + … + 14 =
  11. 11.1 + 3 + 5 + … + 19 =
  12. 12.1 + 3 + 5 + … + 43 =
  13. 13.1 + 2 + 3 + … + 58 =
  14. 14.1 + 2 + 3 + … + 57 =
  15. 15.1 + 3 + 5 + … + 35 =
  16. 16.1 + 2 + 3 + … + 73 =
  17. 17.1 + 2 + 3 + … + 78 =
  18. 18.1 + 2 + 3 + … + 33 =
  19. 19.1 + 3 + 5 + … + 29 =
  20. 20.1 + 2 + 3 + … + 13 =
  21. 21.1 + 2 + 3 + … + 97 =
  22. 22.1 + 2 + 3 + … + 21 =
  23. 23.1 + 2 + 3 + … + 55 =
  24. 24.1 + 2 + 3 + … + 59 =
  25. 25.1 + 2 + 3 + … + 24 =
  26. 26.1 + 3 + 5 + … + 21 =
  27. 27.1 + 2 + 3 + … + 85 =
  28. 28.1 + 2 + 3 + … + 83 =
  29. 29.1 + 2 + 3 + … + 32 =
  30. 30.1 + 2 + 3 + … + 89 =
  31. 31.1 + 3 + 5 + … + 33 =
  32. 32.1 + 2 + 3 + … + 36 =
  33. 33.1 + 2 + 3 + … + 86 =
  34. 34.1 + 2 + 3 + … + 92 =
  35. 35.1 + 3 + 5 + … + 25 =
  36. 36.1 + 2 + 3 + … + 34 =
  37. 37.1 + 3 + 5 + … + 9 =
  38. 38.1 + 2 + 3 + … + 90 =
  39. 39.1 + 2 + 3 + … + 6 =
  40. 40.1 + 2 + 3 + … + 84 =

Answer key

  1. 1485
  2. 1378
  3. 3916
  4. 441
  5. 120
  6. 361
  7. 66
  8. 1225
  9. 49
  10. 105
  11. 100
  12. 484
  13. 1711
  14. 1653
  15. 324
  16. 2701
  17. 3081
  18. 561
  19. 225
  20. 91
  21. 4753
  22. 231
  23. 1540
  24. 1770
  25. 300
  26. 121
  27. 3655
  28. 3486
  29. 528
  30. 4005
  31. 289
  32. 666
  33. 3741
  34. 4278
  35. 169
  36. 595
  37. 25
  38. 4095
  39. 21
  40. 3570

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