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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 226 · 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. 1.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  2. 2.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  7. 7.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?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  11. 11.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  12. 12.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  13. 13.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?
  14. 14.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  18. 18.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  20. 20.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  26. 26.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  27. 27.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?
  28. 28.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  30. 30.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?
  31. 31.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?
  32. 32.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  34. 34.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  35. 35.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  36. 36.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  37. 37.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  38. 38.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?
  39. 39.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?
  40. 40.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =

Answer key

  1. 825
  2. 891
  3. 561
  4. 407
  5. 462
  6. 539
  7. 1067
  8. 286
  9. 594
  10. 231
  11. 1034
  12. 363
  13. 1001
  14. 407
  15. 462
  16. 869
  17. 891
  18. 1089
  19. 649
  20. 451
  21. 528
  22. 979
  23. 484
  24. 418
  25. 814
  26. 286
  27. 781
  28. 638
  29. 671
  30. 847
  31. 495
  32. 550
  33. 737
  34. 506
  35. 561
  36. 495
  37. 572
  38. 550
  39. 517
  40. 1122

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