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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 646 · 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  2. 2.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  3. 3.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. 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. 6.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  7. 7.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?
  8. 8.A leapfrog list starts 8, 1 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): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  10. 10.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?
  11. 11.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?
  12. 12.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  13. 13.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  19. 19.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  20. 20.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?
  21. 21.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  23. 23.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?
  24. 24.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?
  25. 25.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.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?
  28. 28.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  30. 30.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?
  31. 31.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  32. 32.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?
  33. 33.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  36. 36.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?

Answer key

  1. 1056
  2. 1067
  3. 341
  4. 583
  5. 253
  6. 924
  7. 913
  8. 528
  9. 660
  10. 396
  11. 935
  12. 319
  13. 374
  14. 803
  15. 946
  16. 616
  17. 825
  18. 759
  19. 891
  20. 891
  21. 803
  22. 1012
  23. 396
  24. 473
  25. 671
  26. 253
  27. 1111
  28. 1012
  29. 363
  30. 539
  31. 495
  32. 407
  33. 847
  34. 858
  35. 451
  36. 143
  37. 363
  38. 781
  39. 1012
  40. 517

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