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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 608 · 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 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  3. 3.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  4. 4.A leapfrog list starts 2, 4 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): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  8. 8.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  9. 9.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?
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  12. 12.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?
  13. 13.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  14. 14.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?
  15. 15.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  16. 16.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?
  17. 17.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  18. 18.A leapfrog list starts 2, 7 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): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  24. 24.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  28. 28.A leapfrog list starts 5, 3 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 5, 5 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): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  31. 31.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  32. 32.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  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. 34.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  35. 35.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  36. 36.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  37. 37.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  38. 38.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?
  39. 39.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  40. 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =

Answer key

  1. 1122
  2. 396
  3. 781
  4. 462
  5. 836
  6. 737
  7. 407
  8. 891
  9. 825
  10. 341
  11. 869
  12. 979
  13. 979
  14. 935
  15. 1122
  16. 396
  17. 924
  18. 726
  19. 374
  20. 902
  21. 308
  22. 1111
  23. 616
  24. 902
  25. 979
  26. 319
  27. 429
  28. 539
  29. 715
  30. 913
  31. 803
  32. 319
  33. 1122
  34. 1111
  35. 407
  36. 693
  37. 418
  38. 583
  39. 759
  40. 198

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