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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 11 · 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.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?
  2. 2.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  3. 3.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  6. 6.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?
  7. 7.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?
  8. 8.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  9. 9.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  11. 11.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?
  12. 12.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  13. 13.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?
  14. 14.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?
  15. 15.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  16. 16.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?
  17. 17.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?
  18. 18.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  19. 19.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  20. 20.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?
  21. 21.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?
  22. 22.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  23. 23.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?
  24. 24.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?
  25. 25.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  26. 26.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?
  27. 27.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  28. 28.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  33. 33.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  34. 34.A leapfrog list starts 2, 9 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  36. 36.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?
  37. 37.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?
  38. 38.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 737
  2. 319
  3. 693
  4. 693
  5. 880
  6. 506
  7. 847
  8. 704
  9. 968
  10. 572
  11. 1012
  12. 451
  13. 671
  14. 528
  15. 737
  16. 814
  17. 517
  18. 671
  19. 550
  20. 231
  21. 396
  22. 495
  23. 319
  24. 473
  25. 869
  26. 935
  27. 572
  28. 561
  29. 1122
  30. 759
  31. 143
  32. 759
  33. 605
  34. 902
  35. 781
  36. 341
  37. 517
  38. 627
  39. 484
  40. 803

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