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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 498 · 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.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  6. 6.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?
  7. 7.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?
  8. 8.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  9. 9.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?
  10. 10.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  12. 12.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?
  13. 13.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  15. 15.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  18. 18.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?
  19. 19.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  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): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  25. 25.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?
  26. 26.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  27. 27.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?
  28. 28.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  29. 29.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  32. 32.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  33. 33.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?
  34. 34.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?
  35. 35.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  36. 36.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  38. 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 374
  2. 1111
  3. 913
  4. 473
  5. 748
  6. 660
  7. 869
  8. 858
  9. 517
  10. 869
  11. 506
  12. 902
  13. 770
  14. 737
  15. 792
  16. 308
  17. 946
  18. 803
  19. 550
  20. 506
  21. 451
  22. 1287
  23. 616
  24. 968
  25. 1144
  26. 924
  27. 858
  28. 473
  29. 1232
  30. 517
  31. 671
  32. 616
  33. 781
  34. 418
  35. 847
  36. 418
  37. 451
  38. 814
  39. 1067
  40. 451

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