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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 171 · 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. 1.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  3. 3.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  6. 6.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  8. 8.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  12. 12.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?
  13. 13.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?
  14. 14.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  19. 19.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  21. 21.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?
  22. 22.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  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): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  28. 28.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?
  29. 29.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  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.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  35. 35.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?
  36. 36.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  38. 38.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?

Answer key

  1. 231
  2. 814
  3. 638
  4. 891
  5. 726
  6. 847
  7. 231
  8. 1232
  9. 528
  10. 561
  11. 704
  12. 957
  13. 704
  14. 671
  15. 803
  16. 638
  17. 946
  18. 517
  19. 319
  20. 143
  21. 847
  22. 616
  23. 319
  24. 803
  25. 616
  26. 1111
  27. 1089
  28. 693
  29. 770
  30. 671
  31. 473
  32. 143
  33. 836
  34. 418
  35. 517
  36. 550
  37. 814
  38. 1089
  39. 429
  40. 253

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