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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 818 · 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. 1.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  3. 3.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  4. 4.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  5. 5.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  6. 6.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  8. 8.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  10. 10.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  11. 11.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  12. 12.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  13. 13.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  15. 15.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  16. 16.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?
  17. 17.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  18. 18.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?
  19. 19.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  20. 20.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  21. 21.A leapfrog list starts 5, 9 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 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  30. 30.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  32. 32.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  35. 35.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  36. 36.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?

Answer key

  1. 979
  2. 979
  3. 869
  4. 1232
  5. 792
  6. 891
  7. 704
  8. 902
  9. 561
  10. 517
  11. 616
  12. 649
  13. 770
  14. 638
  15. 638
  16. 451
  17. 781
  18. 935
  19. 814
  20. 726
  21. 1067
  22. 341
  23. 484
  24. 583
  25. 704
  26. 880
  27. 506
  28. 836
  29. 374
  30. 638
  31. 583
  32. 528
  33. 1122
  34. 792
  35. 341
  36. 451
  37. 198
  38. 957
  39. 1089
  40. 1199

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