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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 57 · 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. 1.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  2. 2.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?
  3. 3.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  4. 4.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?
  5. 5.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?
  6. 6.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  7. 7.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?
  8. 8.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  9. 9.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?
  10. 10.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?
  11. 11.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  13. 13.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  14. 14.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?
  15. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  18. 18.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  19. 19.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?
  20. 20.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  27. 27.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  28. 28.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?
  29. 29.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?
  30. 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  40. 40.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =

Answer key

  1. 143
  2. 341
  3. 231
  4. 671
  5. 847
  6. 682
  7. 605
  8. 1023
  9. 748
  10. 517
  11. 561
  12. 1023
  13. 495
  14. 231
  15. 198
  16. 682
  17. 143
  18. 583
  19. 781
  20. 660
  21. 407
  22. 671
  23. 836
  24. 528
  25. 363
  26. 1056
  27. 858
  28. 506
  29. 1144
  30. 473
  31. 407
  32. 1056
  33. 539
  34. 759
  35. 484
  36. 506
  37. 253
  38. 704
  39. 1177
  40. 616

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