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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 223 · 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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  22. 22.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  23. 23.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  24. 24.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  25. 25.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  28. 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  29. 29.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  36. 36.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 6, 3 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): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  40. 40.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =

Answer key

  1. 517
  2. 495
  3. 143
  4. 759
  5. 517
  6. 341
  7. 671
  8. 407
  9. 473
  10. 1023
  11. 693
  12. 836
  13. 396
  14. 748
  15. 583
  16. 1034
  17. 231
  18. 781
  19. 1089
  20. 1177
  21. 847
  22. 550
  23. 671
  24. 429
  25. 814
  26. 1144
  27. 946
  28. 902
  29. 726
  30. 891
  31. 671
  32. 429
  33. 539
  34. 253
  35. 363
  36. 869
  37. 1287
  38. 594
  39. 627
  40. 803

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