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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 395 · 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.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  3. 3.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  4. 4.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  5. 5.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  7. 7.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?
  8. 8.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  9. 9.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  10. 10.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?
  11. 11.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  12. 12.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.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?
  15. 15.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  16. 16.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  17. 17.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  20. 20.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  23. 23.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  24. 24.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  26. 26.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  27. 27.A leapfrog list starts 3, 2 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 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  31. 31.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?
  32. 32.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  34. 34.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?
  35. 35.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  38. 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 1199
  2. 429
  3. 1122
  4. 319
  5. 1034
  6. 539
  7. 583
  8. 583
  9. 495
  10. 803
  11. 1111
  12. 583
  13. 759
  14. 495
  15. 605
  16. 374
  17. 1144
  18. 451
  19. 583
  20. 253
  21. 286
  22. 1056
  23. 803
  24. 1056
  25. 902
  26. 1034
  27. 341
  28. 572
  29. 517
  30. 682
  31. 1034
  32. 847
  33. 825
  34. 913
  35. 946
  36. 869
  37. 748
  38. 814
  39. 847
  40. 319

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