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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 555 · 40 questions
TalentJR

The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.

NameDateTime takenScore ___ / 40
  1. 1.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  3. 3.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  4. 4.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  6. 6.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  8. 8.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  9. 9.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  10. 10.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  13. 13.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  14. 14.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  15. 15.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  24. 24.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  26. 26.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  27. 27.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  29. 29.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  34. 34.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  37. 37.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?

Answer key

  1. 319
  2. 319
  3. 748
  4. 550
  5. 671
  6. 495
  7. 484
  8. 561
  9. 891
  10. 858
  11. 1001
  12. 979
  13. 495
  14. 1111
  15. 913
  16. 869
  17. 880
  18. 1034
  19. 286
  20. 451
  21. 748
  22. 374
  23. 737
  24. 671
  25. 605
  26. 451
  27. 231
  28. 517
  29. 286
  30. 583
  31. 1067
  32. 231
  33. 1144
  34. 627
  35. 759
  36. 506
  37. 473
  38. 484
  39. 957
  40. 704

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