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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 283 · 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 + … + 94 =
  2. 2.1 + 2 + 3 + … + 37 =
  3. 3.1 + 2 + 3 + … + 81 =
  4. 4.1 + 2 + 3 + … + 67 =
  5. 5.1 + 2 + 3 + … + 7 =
  6. 6.1 + 3 + 5 + … + 47 =
  7. 7.1 + 3 + 5 + … + 13 =
  8. 8.1 + 3 + 5 + … + 33 =
  9. 9.1 + 3 + 5 + … + 29 =
  10. 10.1 + 3 + 5 + … + 39 =
  11. 11.1 + 2 + 3 + … + 42 =
  12. 12.1 + 2 + 3 + … + 98 =
  13. 13.1 + 3 + 5 + … + 37 =
  14. 14.1 + 2 + 3 + … + 97 =
  15. 15.1 + 2 + 3 + … + 61 =
  16. 16.1 + 2 + 3 + … + 71 =
  17. 17.1 + 2 + 3 + … + 58 =
  18. 18.1 + 2 + 3 + … + 34 =
  19. 19.1 + 3 + 5 + … + 43 =
  20. 20.1 + 2 + 3 + … + 100 =
  21. 21.1 + 2 + 3 + … + 64 =
  22. 22.1 + 2 + 3 + … + 73 =
  23. 23.1 + 2 + 3 + … + 18 =
  24. 24.1 + 2 + 3 + … + 90 =
  25. 25.1 + 3 + 5 + … + 17 =
  26. 26.1 + 2 + 3 + … + 84 =
  27. 27.1 + 2 + 3 + … + 93 =
  28. 28.1 + 2 + 3 + … + 59 =
  29. 29.1 + 2 + 3 + … + 39 =
  30. 30.1 + 3 + 5 + … + 41 =
  31. 31.1 + 3 + 5 + … + 23 =
  32. 32.1 + 2 + 3 + … + 87 =
  33. 33.1 + 2 + 3 + … + 75 =
  34. 34.1 + 2 + 3 + … + 19 =
  35. 35.1 + 3 + 5 + … + 11 =
  36. 36.1 + 3 + 5 + … + 9 =
  37. 37.1 + 2 + 3 + … + 80 =
  38. 38.1 + 2 + 3 + … + 32 =
  39. 39.1 + 3 + 5 + … + 27 =
  40. 40.1 + 2 + 3 + … + 29 =

Answer key

  1. 4465
  2. 703
  3. 3321
  4. 2278
  5. 28
  6. 576
  7. 49
  8. 289
  9. 225
  10. 400
  11. 903
  12. 4851
  13. 361
  14. 4753
  15. 1891
  16. 2556
  17. 1711
  18. 595
  19. 484
  20. 5050
  21. 2080
  22. 2701
  23. 171
  24. 4095
  25. 81
  26. 3570
  27. 4371
  28. 1770
  29. 780
  30. 441
  31. 144
  32. 3828
  33. 2850
  34. 190
  35. 36
  36. 25
  37. 3240
  38. 528
  39. 196
  40. 435

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