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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 723 · 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): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  2. 2.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  7. 7.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  8. 8.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  10. 10.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  11. 11.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?
  12. 12.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?
  13. 13.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  14. 14.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?
  15. 15.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  20. 20.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  22. 22.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  23. 23.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  24. 24.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  25. 25.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?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  28. 28.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?
  29. 29.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  30. 30.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  38. 38.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 363
  2. 770
  3. 1122
  4. 847
  5. 253
  6. 726
  7. 649
  8. 418
  9. 924
  10. 847
  11. 583
  12. 341
  13. 891
  14. 891
  15. 517
  16. 671
  17. 913
  18. 649
  19. 759
  20. 253
  21. 1034
  22. 143
  23. 1199
  24. 803
  25. 429
  26. 902
  27. 1012
  28. 308
  29. 616
  30. 462
  31. 605
  32. 198
  33. 550
  34. 781
  35. 484
  36. 506
  37. 924
  38. 759
  39. 682
  40. 1232

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