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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 199 · 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  2. 2.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  3. 3.A leapfrog list starts 7, 7 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 7, 2 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 7, 6 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 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.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?
  10. 10.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  11. 11.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  12. 12.A leapfrog list starts 8, 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 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  14. 14.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  16. 16.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?
  17. 17.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.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?
  19. 19.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?
  20. 20.A leapfrog list starts 5, 7 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): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  22. 22.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?
  23. 23.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?
  24. 24.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  25. 25.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?
  26. 26.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  27. 27.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  34. 34.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?
  35. 35.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?
  36. 36.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  37. 37.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  38. 38.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  39. 39.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?
  40. 40.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 308
  2. 462
  3. 1001
  4. 902
  5. 561
  6. 913
  7. 539
  8. 715
  9. 341
  10. 1067
  11. 605
  12. 616
  13. 715
  14. 759
  15. 715
  16. 1089
  17. 781
  18. 583
  19. 847
  20. 891
  21. 451
  22. 429
  23. 319
  24. 583
  25. 374
  26. 319
  27. 605
  28. 473
  29. 484
  30. 517
  31. 1144
  32. 704
  33. 781
  34. 462
  35. 660
  36. 286
  37. 253
  38. 869
  39. 1144
  40. 1067

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