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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 880 · 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. 1.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  2. 2.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?
  3. 3.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  4. 4.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?
  5. 5.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  6. 6.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?
  7. 7.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.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?
  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.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?
  12. 12.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  13. 13.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  14. 14.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?
  15. 15.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?
  16. 16.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  17. 17.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  20. 20.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?
  21. 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  22. 22.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  28. 28.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  31. 31.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  33. 33.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  35. 35.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  38. 38.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 1034
  2. 638
  3. 726
  4. 891
  5. 484
  6. 231
  7. 374
  8. 836
  9. 319
  10. 1023
  11. 319
  12. 836
  13. 792
  14. 517
  15. 594
  16. 143
  17. 1023
  18. 583
  19. 649
  20. 143
  21. 605
  22. 1199
  23. 429
  24. 418
  25. 627
  26. 396
  27. 891
  28. 979
  29. 869
  30. 1144
  31. 1287
  32. 924
  33. 825
  34. 616
  35. 407
  36. 473
  37. 847
  38. 1232
  39. 1111
  40. 880

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