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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 525 · 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. 1.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  2. 2.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  3. 3.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  4. 4.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?
  5. 5.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?
  6. 6.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.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?
  10. 10.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  11. 11.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  12. 12.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  13. 13.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  14. 14.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  21. 21.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  22. 22.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  24. 24.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?
  25. 25.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  26. 26.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  27. 27.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?
  28. 28.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  29. 29.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  30. 30.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?
  31. 31.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?
  32. 32.A leapfrog list starts 1, 6 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 4, 5 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 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  36. 36.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?
  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.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  40. 40.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =

Answer key

  1. 1232
  2. 231
  3. 517
  4. 550
  5. 935
  6. 1122
  7. 308
  8. 517
  9. 803
  10. 473
  11. 506
  12. 946
  13. 759
  14. 847
  15. 781
  16. 946
  17. 539
  18. 682
  19. 308
  20. 847
  21. 682
  22. 737
  23. 726
  24. 814
  25. 363
  26. 341
  27. 605
  28. 836
  29. 1122
  30. 671
  31. 143
  32. 583
  33. 660
  34. 594
  35. 891
  36. 1012
  37. 473
  38. 759
  39. 968
  40. 847

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