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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 786 · 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): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  2. 2.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  4. 4.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  5. 5.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?
  6. 6.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?
  7. 7.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  8. 8.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  9. 9.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  10. 10.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?
  11. 11.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?
  12. 12.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  13. 13.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?
  14. 14.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  15. 15.A leapfrog list starts 9, 7 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  17. 17.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  18. 18.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?
  19. 19.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  21. 21.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  22. 22.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?
  23. 23.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?
  24. 24.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  28. 28.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  30. 30.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  32. 32.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  33. 33.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  35. 35.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  38. 38.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?
  39. 39.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  40. 40.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1067
  2. 913
  3. 539
  4. 517
  5. 1144
  6. 913
  7. 715
  8. 891
  9. 231
  10. 429
  11. 1034
  12. 1001
  13. 1067
  14. 759
  15. 1111
  16. 308
  17. 836
  18. 550
  19. 418
  20. 924
  21. 451
  22. 671
  23. 495
  24. 968
  25. 979
  26. 759
  27. 968
  28. 935
  29. 484
  30. 825
  31. 341
  32. 594
  33. 506
  34. 143
  35. 715
  36. 748
  37. 286
  38. 693
  39. 660
  40. 924

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