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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 388 · 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 + … + 57 =
  2. 2.1 + 3 + 5 + … + 49 =
  3. 3.1 + 3 + 5 + … + 9 =
  4. 4.1 + 2 + 3 + … + 67 =
  5. 5.1 + 3 + 5 + … + 11 =
  6. 6.1 + 2 + 3 + … + 46 =
  7. 7.1 + 2 + 3 + … + 51 =
  8. 8.1 + 2 + 3 + … + 75 =
  9. 9.1 + 2 + 3 + … + 23 =
  10. 10.1 + 3 + 5 + … + 31 =
  11. 11.1 + 2 + 3 + … + 52 =
  12. 12.1 + 2 + 3 + … + 11 =
  13. 13.1 + 3 + 5 + … + 17 =
  14. 14.1 + 2 + 3 + … + 28 =
  15. 15.1 + 2 + 3 + … + 70 =
  16. 16.1 + 2 + 3 + … + 98 =
  17. 17.1 + 2 + 3 + … + 29 =
  18. 18.1 + 3 + 5 + … + 43 =
  19. 19.1 + 2 + 3 + … + 13 =
  20. 20.1 + 2 + 3 + … + 14 =
  21. 21.1 + 2 + 3 + … + 89 =
  22. 22.1 + 3 + 5 + … + 15 =
  23. 23.1 + 3 + 5 + … + 19 =
  24. 24.1 + 3 + 5 + … + 41 =
  25. 25.1 + 2 + 3 + … + 47 =
  26. 26.1 + 2 + 3 + … + 60 =
  27. 27.1 + 2 + 3 + … + 95 =
  28. 28.1 + 2 + 3 + … + 100 =
  29. 29.1 + 2 + 3 + … + 91 =
  30. 30.1 + 2 + 3 + … + 50 =
  31. 31.1 + 2 + 3 + … + 61 =
  32. 32.1 + 3 + 5 + … + 37 =
  33. 33.1 + 2 + 3 + … + 6 =
  34. 34.1 + 3 + 5 + … + 39 =
  35. 35.1 + 2 + 3 + … + 25 =
  36. 36.1 + 3 + 5 + … + 35 =
  37. 37.1 + 2 + 3 + … + 94 =
  38. 38.1 + 2 + 3 + … + 77 =
  39. 39.1 + 2 + 3 + … + 30 =
  40. 40.1 + 2 + 3 + … + 19 =

Answer key

  1. 1653
  2. 625
  3. 25
  4. 2278
  5. 36
  6. 1081
  7. 1326
  8. 2850
  9. 276
  10. 256
  11. 1378
  12. 66
  13. 81
  14. 406
  15. 2485
  16. 4851
  17. 435
  18. 484
  19. 91
  20. 105
  21. 4005
  22. 64
  23. 100
  24. 441
  25. 1128
  26. 1830
  27. 4560
  28. 5050
  29. 4186
  30. 1275
  31. 1891
  32. 361
  33. 21
  34. 400
  35. 325
  36. 324
  37. 4465
  38. 3003
  39. 465
  40. 190

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