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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 730 · 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. 1.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  2. 2.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  3. 3.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?
  4. 4.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?
  5. 5.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  7. 7.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  12. 12.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  17. 17.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  18. 18.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  22. 22.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?
  23. 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  24. 24.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  25. 25.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?
  26. 26.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  27. 27.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?
  28. 28.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?
  29. 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  30. 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  31. 31.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  33. 33.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  35. 35.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  36. 36.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  37. 37.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  40. 40.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?

Answer key

  1. 726
  2. 979
  3. 550
  4. 748
  5. 407
  6. 1067
  7. 1056
  8. 517
  9. 781
  10. 506
  11. 561
  12. 539
  13. 847
  14. 429
  15. 473
  16. 880
  17. 1001
  18. 594
  19. 517
  20. 1034
  21. 759
  22. 561
  23. 363
  24. 341
  25. 451
  26. 935
  27. 1067
  28. 528
  29. 594
  30. 473
  31. 649
  32. 770
  33. 1122
  34. 1012
  35. 374
  36. 231
  37. 671
  38. 484
  39. 396
  40. 693

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