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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 128 · 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, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  4. 4.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?
  5. 5.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?
  6. 6.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  9. 9.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  10. 10.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  11. 11.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  12. 12.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  13. 13.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?
  14. 14.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  17. 17.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?
  18. 18.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  19. 19.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?
  20. 20.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  23. 23.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  24. 24.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  36. 36.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?
  37. 37.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  38. 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  40. 40.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =

Answer key

  1. 946
  2. 781
  3. 770
  4. 902
  5. 484
  6. 231
  7. 825
  8. 671
  9. 561
  10. 726
  11. 759
  12. 803
  13. 1023
  14. 1067
  15. 957
  16. 484
  17. 627
  18. 143
  19. 429
  20. 583
  21. 407
  22. 594
  23. 770
  24. 814
  25. 671
  26. 451
  27. 550
  28. 341
  29. 858
  30. 935
  31. 1232
  32. 836
  33. 1287
  34. 1144
  35. 682
  36. 407
  37. 506
  38. 528
  39. 935
  40. 825

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