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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 429 · 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 + … + 44 =
  2. 2.1 + 2 + 3 + … + 19 =
  3. 3.1 + 2 + 3 + … + 73 =
  4. 4.1 + 2 + 3 + … + 16 =
  5. 5.1 + 3 + 5 + … + 31 =
  6. 6.1 + 2 + 3 + … + 14 =
  7. 7.1 + 3 + 5 + … + 49 =
  8. 8.1 + 2 + 3 + … + 33 =
  9. 9.1 + 2 + 3 + … + 76 =
  10. 10.1 + 2 + 3 + … + 25 =
  11. 11.1 + 2 + 3 + … + 57 =
  12. 12.1 + 3 + 5 + … + 39 =
  13. 13.1 + 2 + 3 + … + 86 =
  14. 14.1 + 2 + 3 + … + 68 =
  15. 15.1 + 3 + 5 + … + 23 =
  16. 16.1 + 3 + 5 + … + 47 =
  17. 17.1 + 2 + 3 + … + 64 =
  18. 18.1 + 2 + 3 + … + 61 =
  19. 19.1 + 2 + 3 + … + 58 =
  20. 20.1 + 2 + 3 + … + 79 =
  21. 21.1 + 3 + 5 + … + 19 =
  22. 22.1 + 2 + 3 + … + 89 =
  23. 23.1 + 2 + 3 + … + 52 =
  24. 24.1 + 2 + 3 + … + 54 =
  25. 25.1 + 2 + 3 + … + 45 =
  26. 26.1 + 2 + 3 + … + 99 =
  27. 27.1 + 3 + 5 + … + 27 =
  28. 28.1 + 2 + 3 + … + 97 =
  29. 29.1 + 2 + 3 + … + 74 =
  30. 30.1 + 2 + 3 + … + 66 =
  31. 31.1 + 2 + 3 + … + 85 =
  32. 32.1 + 2 + 3 + … + 88 =
  33. 33.1 + 3 + 5 + … + 17 =
  34. 34.1 + 2 + 3 + … + 81 =
  35. 35.1 + 3 + 5 + … + 45 =
  36. 36.1 + 2 + 3 + … + 100 =
  37. 37.1 + 2 + 3 + … + 11 =
  38. 38.1 + 2 + 3 + … + 83 =
  39. 39.1 + 2 + 3 + … + 95 =
  40. 40.1 + 2 + 3 + … + 59 =

Answer key

  1. 990
  2. 190
  3. 2701
  4. 136
  5. 256
  6. 105
  7. 625
  8. 561
  9. 2926
  10. 325
  11. 1653
  12. 400
  13. 3741
  14. 2346
  15. 144
  16. 576
  17. 2080
  18. 1891
  19. 1711
  20. 3160
  21. 100
  22. 4005
  23. 1378
  24. 1485
  25. 1035
  26. 4950
  27. 196
  28. 4753
  29. 2775
  30. 2211
  31. 3655
  32. 3916
  33. 81
  34. 3321
  35. 529
  36. 5050
  37. 66
  38. 3486
  39. 4560
  40. 1770

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