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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 936 · 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): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  5. 5.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  6. 6.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?
  7. 7.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.A leapfrog list starts 4, 5 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 5, 9 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 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  13. 13.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  15. 15.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?
  16. 16.A leapfrog list starts 2, 2 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): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  18. 18.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?
  19. 19.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  21. 21.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  22. 22.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  24. 24.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  26. 26.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  27. 27.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  28. 28.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?
  29. 29.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  30. 30.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  31. 31.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  33. 33.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  34. 34.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  35. 35.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  36. 36.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  37. 37.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  38. 38.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?
  39. 39.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?
  40. 40.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =

Answer key

  1. 583
  2. 1122
  3. 792
  4. 308
  5. 1012
  6. 671
  7. 363
  8. 473
  9. 660
  10. 1067
  11. 528
  12. 583
  13. 682
  14. 913
  15. 627
  16. 286
  17. 462
  18. 517
  19. 143
  20. 572
  21. 957
  22. 506
  23. 561
  24. 693
  25. 1177
  26. 198
  27. 682
  28. 198
  29. 473
  30. 946
  31. 363
  32. 1144
  33. 836
  34. 825
  35. 1001
  36. 605
  37. 341
  38. 495
  39. 1056
  40. 869

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