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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 149 · 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 + … + 62 =
  2. 2.1 + 3 + 5 + … + 13 =
  3. 3.1 + 2 + 3 + … + 46 =
  4. 4.1 + 3 + 5 + … + 19 =
  5. 5.1 + 3 + 5 + … + 9 =
  6. 6.1 + 2 + 3 + … + 31 =
  7. 7.1 + 3 + 5 + … + 49 =
  8. 8.1 + 2 + 3 + … + 71 =
  9. 9.1 + 2 + 3 + … + 75 =
  10. 10.1 + 2 + 3 + … + 84 =
  11. 11.1 + 2 + 3 + … + 7 =
  12. 12.1 + 2 + 3 + … + 54 =
  13. 13.1 + 3 + 5 + … + 39 =
  14. 14.1 + 2 + 3 + … + 38 =
  15. 15.1 + 2 + 3 + … + 91 =
  16. 16.1 + 2 + 3 + … + 67 =
  17. 17.1 + 2 + 3 + … + 19 =
  18. 18.1 + 2 + 3 + … + 40 =
  19. 19.1 + 2 + 3 + … + 96 =
  20. 20.1 + 3 + 5 + … + 17 =
  21. 21.1 + 2 + 3 + … + 10 =
  22. 22.1 + 3 + 5 + … + 41 =
  23. 23.1 + 2 + 3 + … + 60 =
  24. 24.1 + 3 + 5 + … + 37 =
  25. 25.1 + 2 + 3 + … + 92 =
  26. 26.1 + 2 + 3 + … + 25 =
  27. 27.1 + 2 + 3 + … + 83 =
  28. 28.1 + 2 + 3 + … + 30 =
  29. 29.1 + 2 + 3 + … + 6 =
  30. 30.1 + 2 + 3 + … + 21 =
  31. 31.1 + 2 + 3 + … + 41 =
  32. 32.1 + 2 + 3 + … + 43 =
  33. 33.1 + 2 + 3 + … + 15 =
  34. 34.1 + 2 + 3 + … + 52 =
  35. 35.1 + 3 + 5 + … + 27 =
  36. 36.1 + 2 + 3 + … + 100 =
  37. 37.1 + 2 + 3 + … + 63 =
  38. 38.1 + 2 + 3 + … + 22 =
  39. 39.1 + 2 + 3 + … + 70 =
  40. 40.1 + 2 + 3 + … + 33 =

Answer key

  1. 1953
  2. 49
  3. 1081
  4. 100
  5. 25
  6. 496
  7. 625
  8. 2556
  9. 2850
  10. 3570
  11. 28
  12. 1485
  13. 400
  14. 741
  15. 4186
  16. 2278
  17. 190
  18. 820
  19. 4656
  20. 81
  21. 55
  22. 441
  23. 1830
  24. 361
  25. 4278
  26. 325
  27. 3486
  28. 465
  29. 21
  30. 231
  31. 861
  32. 946
  33. 120
  34. 1378
  35. 196
  36. 5050
  37. 2016
  38. 253
  39. 2485
  40. 561

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