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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 290 · 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 + … + 32 =
  2. 2.1 + 2 + 3 + … + 16 =
  3. 3.1 + 2 + 3 + … + 41 =
  4. 4.1 + 2 + 3 + … + 53 =
  5. 5.1 + 3 + 5 + … + 17 =
  6. 6.1 + 2 + 3 + … + 13 =
  7. 7.1 + 2 + 3 + … + 94 =
  8. 8.1 + 3 + 5 + … + 49 =
  9. 9.1 + 3 + 5 + … + 37 =
  10. 10.1 + 2 + 3 + … + 44 =
  11. 11.1 + 2 + 3 + … + 48 =
  12. 12.1 + 3 + 5 + … + 9 =
  13. 13.1 + 2 + 3 + … + 90 =
  14. 14.1 + 3 + 5 + … + 19 =
  15. 15.1 + 2 + 3 + … + 36 =
  16. 16.1 + 2 + 3 + … + 67 =
  17. 17.1 + 2 + 3 + … + 10 =
  18. 18.1 + 2 + 3 + … + 73 =
  19. 19.1 + 3 + 5 + … + 41 =
  20. 20.1 + 2 + 3 + … + 11 =
  21. 21.1 + 3 + 5 + … + 39 =
  22. 22.1 + 2 + 3 + … + 66 =
  23. 23.1 + 3 + 5 + … + 11 =
  24. 24.1 + 2 + 3 + … + 72 =
  25. 25.1 + 2 + 3 + … + 12 =
  26. 26.1 + 2 + 3 + … + 18 =
  27. 27.1 + 2 + 3 + … + 30 =
  28. 28.1 + 2 + 3 + … + 14 =
  29. 29.1 + 2 + 3 + … + 43 =
  30. 30.1 + 2 + 3 + … + 46 =
  31. 31.1 + 2 + 3 + … + 96 =
  32. 32.1 + 2 + 3 + … + 15 =
  33. 33.1 + 2 + 3 + … + 85 =
  34. 34.1 + 2 + 3 + … + 40 =
  35. 35.1 + 3 + 5 + … + 33 =
  36. 36.1 + 2 + 3 + … + 54 =
  37. 37.1 + 2 + 3 + … + 22 =
  38. 38.1 + 2 + 3 + … + 82 =
  39. 39.1 + 2 + 3 + … + 86 =
  40. 40.1 + 2 + 3 + … + 76 =

Answer key

  1. 528
  2. 136
  3. 861
  4. 1431
  5. 81
  6. 91
  7. 4465
  8. 625
  9. 361
  10. 990
  11. 1176
  12. 25
  13. 4095
  14. 100
  15. 666
  16. 2278
  17. 55
  18. 2701
  19. 441
  20. 66
  21. 400
  22. 2211
  23. 36
  24. 2628
  25. 78
  26. 171
  27. 465
  28. 105
  29. 946
  30. 1081
  31. 4656
  32. 120
  33. 3655
  34. 820
  35. 289
  36. 1485
  37. 253
  38. 3403
  39. 3741
  40. 2926

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