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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 962 · 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 + … + 95 =
  2. 2.1 + 2 + 3 + … + 29 =
  3. 3.1 + 2 + 3 + … + 75 =
  4. 4.1 + 3 + 5 + … + 29 =
  5. 5.1 + 3 + 5 + … + 43 =
  6. 6.1 + 2 + 3 + … + 31 =
  7. 7.1 + 3 + 5 + … + 37 =
  8. 8.1 + 2 + 3 + … + 58 =
  9. 9.1 + 2 + 3 + … + 11 =
  10. 10.1 + 2 + 3 + … + 19 =
  11. 11.1 + 2 + 3 + … + 22 =
  12. 12.1 + 3 + 5 + … + 23 =
  13. 13.1 + 2 + 3 + … + 72 =
  14. 14.1 + 2 + 3 + … + 77 =
  15. 15.1 + 2 + 3 + … + 51 =
  16. 16.1 + 2 + 3 + … + 52 =
  17. 17.1 + 2 + 3 + … + 98 =
  18. 18.1 + 2 + 3 + … + 68 =
  19. 19.1 + 2 + 3 + … + 50 =
  20. 20.1 + 2 + 3 + … + 76 =
  21. 21.1 + 3 + 5 + … + 27 =
  22. 22.1 + 2 + 3 + … + 63 =
  23. 23.1 + 2 + 3 + … + 14 =
  24. 24.1 + 2 + 3 + … + 27 =
  25. 25.1 + 2 + 3 + … + 39 =
  26. 26.1 + 2 + 3 + … + 70 =
  27. 27.1 + 2 + 3 + … + 30 =
  28. 28.1 + 3 + 5 + … + 47 =
  29. 29.1 + 3 + 5 + … + 11 =
  30. 30.1 + 3 + 5 + … + 33 =
  31. 31.1 + 2 + 3 + … + 93 =
  32. 32.1 + 2 + 3 + … + 99 =
  33. 33.1 + 2 + 3 + … + 37 =
  34. 34.1 + 3 + 5 + … + 25 =
  35. 35.1 + 2 + 3 + … + 10 =
  36. 36.1 + 2 + 3 + … + 15 =
  37. 37.1 + 2 + 3 + … + 92 =
  38. 38.1 + 3 + 5 + … + 45 =
  39. 39.1 + 2 + 3 + … + 81 =
  40. 40.1 + 2 + 3 + … + 33 =

Answer key

  1. 4560
  2. 435
  3. 2850
  4. 225
  5. 484
  6. 496
  7. 361
  8. 1711
  9. 66
  10. 190
  11. 253
  12. 144
  13. 2628
  14. 3003
  15. 1326
  16. 1378
  17. 4851
  18. 2346
  19. 1275
  20. 2926
  21. 196
  22. 2016
  23. 105
  24. 378
  25. 780
  26. 2485
  27. 465
  28. 576
  29. 36
  30. 289
  31. 4371
  32. 4950
  33. 703
  34. 169
  35. 55
  36. 120
  37. 4278
  38. 529
  39. 3321
  40. 561

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