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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 904 · 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 + … + 22 =
  2. 2.1 + 2 + 3 + … + 99 =
  3. 3.1 + 2 + 3 + … + 33 =
  4. 4.1 + 2 + 3 + … + 53 =
  5. 5.1 + 2 + 3 + … + 44 =
  6. 6.1 + 2 + 3 + … + 13 =
  7. 7.1 + 2 + 3 + … + 56 =
  8. 8.1 + 2 + 3 + … + 85 =
  9. 9.1 + 3 + 5 + … + 49 =
  10. 10.1 + 2 + 3 + … + 84 =
  11. 11.1 + 2 + 3 + … + 25 =
  12. 12.1 + 2 + 3 + … + 46 =
  13. 13.1 + 2 + 3 + … + 59 =
  14. 14.1 + 3 + 5 + … + 19 =
  15. 15.1 + 2 + 3 + … + 7 =
  16. 16.1 + 2 + 3 + … + 93 =
  17. 17.1 + 2 + 3 + … + 42 =
  18. 18.1 + 2 + 3 + … + 55 =
  19. 19.1 + 2 + 3 + … + 24 =
  20. 20.1 + 2 + 3 + … + 26 =
  21. 21.1 + 2 + 3 + … + 87 =
  22. 22.1 + 3 + 5 + … + 13 =
  23. 23.1 + 2 + 3 + … + 11 =
  24. 24.1 + 2 + 3 + … + 15 =
  25. 25.1 + 2 + 3 + … + 27 =
  26. 26.1 + 2 + 3 + … + 34 =
  27. 27.1 + 2 + 3 + … + 63 =
  28. 28.1 + 2 + 3 + … + 54 =
  29. 29.1 + 3 + 5 + … + 23 =
  30. 30.1 + 2 + 3 + … + 31 =
  31. 31.1 + 3 + 5 + … + 17 =
  32. 32.1 + 2 + 3 + … + 69 =
  33. 33.1 + 2 + 3 + … + 14 =
  34. 34.1 + 2 + 3 + … + 79 =
  35. 35.1 + 2 + 3 + … + 94 =
  36. 36.1 + 2 + 3 + … + 52 =
  37. 37.1 + 3 + 5 + … + 11 =
  38. 38.1 + 3 + 5 + … + 45 =
  39. 39.1 + 3 + 5 + … + 41 =
  40. 40.1 + 2 + 3 + … + 41 =

Answer key

  1. 253
  2. 4950
  3. 561
  4. 1431
  5. 990
  6. 91
  7. 1596
  8. 3655
  9. 625
  10. 3570
  11. 325
  12. 1081
  13. 1770
  14. 100
  15. 28
  16. 4371
  17. 903
  18. 1540
  19. 300
  20. 351
  21. 3828
  22. 49
  23. 66
  24. 120
  25. 378
  26. 595
  27. 2016
  28. 1485
  29. 144
  30. 496
  31. 81
  32. 2415
  33. 105
  34. 3160
  35. 4465
  36. 1378
  37. 36
  38. 529
  39. 441
  40. 861

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