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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 760 · 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.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?
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  3. 3.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  8. 8.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?
  9. 9.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  10. 10.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  13. 13.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  14. 14.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  17. 17.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?
  18. 18.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. 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.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?
  22. 22.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?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  28. 28.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?
  29. 29.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?
  30. 30.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  33. 33.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  34. 34.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  35. 35.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  36. 36.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  37. 37.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?
  38. 38.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?
  39. 39.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  40. 40.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 418
  2. 1144
  3. 143
  4. 759
  5. 583
  6. 1089
  7. 550
  8. 869
  9. 583
  10. 682
  11. 616
  12. 286
  13. 880
  14. 627
  15. 638
  16. 847
  17. 1122
  18. 748
  19. 451
  20. 902
  21. 671
  22. 726
  23. 726
  24. 308
  25. 473
  26. 847
  27. 858
  28. 407
  29. 957
  30. 1056
  31. 902
  32. 869
  33. 671
  34. 1023
  35. 1111
  36. 847
  37. 583
  38. 550
  39. 198
  40. 198

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