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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 534 · 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 + 3 + 5 + … + 13 =
  2. 2.1 + 2 + 3 + … + 38 =
  3. 3.1 + 2 + 3 + … + 57 =
  4. 4.1 + 2 + 3 + … + 51 =
  5. 5.1 + 2 + 3 + … + 10 =
  6. 6.1 + 2 + 3 + … + 11 =
  7. 7.1 + 3 + 5 + … + 43 =
  8. 8.1 + 3 + 5 + … + 19 =
  9. 9.1 + 2 + 3 + … + 75 =
  10. 10.1 + 2 + 3 + … + 52 =
  11. 11.1 + 2 + 3 + … + 84 =
  12. 12.1 + 2 + 3 + … + 20 =
  13. 13.1 + 2 + 3 + … + 91 =
  14. 14.1 + 2 + 3 + … + 98 =
  15. 15.1 + 3 + 5 + … + 27 =
  16. 16.1 + 2 + 3 + … + 87 =
  17. 17.1 + 2 + 3 + … + 19 =
  18. 18.1 + 2 + 3 + … + 83 =
  19. 19.1 + 2 + 3 + … + 77 =
  20. 20.1 + 2 + 3 + … + 81 =
  21. 21.1 + 3 + 5 + … + 47 =
  22. 22.1 + 2 + 3 + … + 16 =
  23. 23.1 + 3 + 5 + … + 41 =
  24. 24.1 + 2 + 3 + … + 53 =
  25. 25.1 + 3 + 5 + … + 45 =
  26. 26.1 + 3 + 5 + … + 25 =
  27. 27.1 + 3 + 5 + … + 49 =
  28. 28.1 + 2 + 3 + … + 62 =
  29. 29.1 + 2 + 3 + … + 54 =
  30. 30.1 + 2 + 3 + … + 60 =
  31. 31.1 + 2 + 3 + … + 55 =
  32. 32.1 + 2 + 3 + … + 99 =
  33. 33.1 + 2 + 3 + … + 37 =
  34. 34.1 + 2 + 3 + … + 8 =
  35. 35.1 + 2 + 3 + … + 46 =
  36. 36.1 + 2 + 3 + … + 44 =
  37. 37.1 + 3 + 5 + … + 29 =
  38. 38.1 + 3 + 5 + … + 33 =
  39. 39.1 + 2 + 3 + … + 70 =
  40. 40.1 + 2 + 3 + … + 97 =

Answer key

  1. 49
  2. 741
  3. 1653
  4. 1326
  5. 55
  6. 66
  7. 484
  8. 100
  9. 2850
  10. 1378
  11. 3570
  12. 210
  13. 4186
  14. 4851
  15. 196
  16. 3828
  17. 190
  18. 3486
  19. 3003
  20. 3321
  21. 576
  22. 136
  23. 441
  24. 1431
  25. 529
  26. 169
  27. 625
  28. 1953
  29. 1485
  30. 1830
  31. 1540
  32. 4950
  33. 703
  34. 36
  35. 1081
  36. 990
  37. 225
  38. 289
  39. 2485
  40. 4753

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