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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 56 · 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 + … + 43 =
  2. 2.1 + 2 + 3 + … + 54 =
  3. 3.1 + 2 + 3 + … + 88 =
  4. 4.1 + 2 + 3 + … + 22 =
  5. 5.1 + 2 + 3 + … + 77 =
  6. 6.1 + 2 + 3 + … + 46 =
  7. 7.1 + 2 + 3 + … + 75 =
  8. 8.1 + 2 + 3 + … + 26 =
  9. 9.1 + 2 + 3 + … + 7 =
  10. 10.1 + 2 + 3 + … + 60 =
  11. 11.1 + 3 + 5 + … + 11 =
  12. 12.1 + 3 + 5 + … + 41 =
  13. 13.1 + 2 + 3 + … + 91 =
  14. 14.1 + 2 + 3 + … + 27 =
  15. 15.1 + 2 + 3 + … + 13 =
  16. 16.1 + 3 + 5 + … + 17 =
  17. 17.1 + 2 + 3 + … + 98 =
  18. 18.1 + 3 + 5 + … + 21 =
  19. 19.1 + 2 + 3 + … + 71 =
  20. 20.1 + 3 + 5 + … + 13 =
  21. 21.1 + 2 + 3 + … + 29 =
  22. 22.1 + 2 + 3 + … + 78 =
  23. 23.1 + 2 + 3 + … + 6 =
  24. 24.1 + 3 + 5 + … + 31 =
  25. 25.1 + 2 + 3 + … + 14 =
  26. 26.1 + 2 + 3 + … + 61 =
  27. 27.1 + 2 + 3 + … + 76 =
  28. 28.1 + 2 + 3 + … + 85 =
  29. 29.1 + 2 + 3 + … + 51 =
  30. 30.1 + 2 + 3 + … + 31 =
  31. 31.1 + 2 + 3 + … + 97 =
  32. 32.1 + 2 + 3 + … + 81 =
  33. 33.1 + 3 + 5 + … + 35 =
  34. 34.1 + 2 + 3 + … + 82 =
  35. 35.1 + 2 + 3 + … + 83 =
  36. 36.1 + 3 + 5 + … + 47 =
  37. 37.1 + 2 + 3 + … + 9 =
  38. 38.1 + 2 + 3 + … + 90 =
  39. 39.1 + 3 + 5 + … + 45 =
  40. 40.1 + 2 + 3 + … + 73 =

Answer key

  1. 946
  2. 1485
  3. 3916
  4. 253
  5. 3003
  6. 1081
  7. 2850
  8. 351
  9. 28
  10. 1830
  11. 36
  12. 441
  13. 4186
  14. 378
  15. 91
  16. 81
  17. 4851
  18. 121
  19. 2556
  20. 49
  21. 435
  22. 3081
  23. 21
  24. 256
  25. 105
  26. 1891
  27. 2926
  28. 3655
  29. 1326
  30. 496
  31. 4753
  32. 3321
  33. 324
  34. 3403
  35. 3486
  36. 576
  37. 45
  38. 4095
  39. 529
  40. 2701

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