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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 921 · 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  4. 4.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?
  5. 5.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  7. 7.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  8. 8.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?
  9. 9.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?
  10. 10.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  11. 11.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  13. 13.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  14. 14.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  15. 15.A leapfrog list starts 6, 6 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 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  19. 19.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?
  20. 20.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?
  21. 21.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  22. 22.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  23. 23.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  25. 25.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  28. 28.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  29. 29.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?
  30. 30.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  32. 32.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  36. 36.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  37. 37.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?
  38. 38.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  39. 39.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 308
  2. 407
  3. 583
  4. 836
  5. 396
  6. 1144
  7. 1001
  8. 462
  9. 286
  10. 902
  11. 495
  12. 605
  13. 517
  14. 748
  15. 858
  16. 484
  17. 407
  18. 407
  19. 495
  20. 671
  21. 594
  22. 704
  23. 374
  24. 1122
  25. 198
  26. 1012
  27. 671
  28. 759
  29. 429
  30. 880
  31. 682
  32. 1287
  33. 968
  34. 451
  35. 1177
  36. 462
  37. 473
  38. 726
  39. 253
  40. 649

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