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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 899 · 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  5. 5.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  6. 6.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?
  7. 7.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  11. 11.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?
  12. 12.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  13. 13.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?
  14. 14.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.A leapfrog list starts 3, 8 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  18. 18.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?
  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): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  23. 23.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?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  28. 28.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?
  29. 29.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  30. 30.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  31. 31.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?
  32. 32.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  37. 37.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?
  38. 38.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  40. 40.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 561
  2. 528
  3. 803
  4. 935
  5. 836
  6. 1056
  7. 429
  8. 781
  9. 825
  10. 253
  11. 979
  12. 671
  13. 506
  14. 616
  15. 374
  16. 869
  17. 869
  18. 319
  19. 418
  20. 198
  21. 231
  22. 605
  23. 1012
  24. 429
  25. 737
  26. 726
  27. 517
  28. 1034
  29. 649
  30. 363
  31. 418
  32. 1089
  33. 935
  34. 286
  35. 1144
  36. 1089
  37. 451
  38. 1177
  39. 814
  40. 605

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