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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 712 · 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. 1.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  3. 3.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  4. 4.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  5. 5.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  14. 14.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  15. 15.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  18. 18.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  21. 21.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  22. 22.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  23. 23.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?
  24. 24.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  27. 27.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  30. 30.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  31. 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  32. 32.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  37. 37.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  40. 40.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =

Answer key

  1. 979
  2. 143
  3. 253
  4. 473
  5. 517
  6. 231
  7. 418
  8. 363
  9. 1012
  10. 308
  11. 550
  12. 902
  13. 726
  14. 286
  15. 946
  16. 495
  17. 847
  18. 880
  19. 627
  20. 726
  21. 231
  22. 396
  23. 704
  24. 858
  25. 979
  26. 462
  27. 759
  28. 792
  29. 715
  30. 198
  31. 616
  32. 550
  33. 737
  34. 462
  35. 693
  36. 1023
  37. 781
  38. 759
  39. 803
  40. 539

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