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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 623 · 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  2. 2.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  3. 3.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  4. 4.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  5. 5.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  15. 15.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?
  16. 16.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  17. 17.A leapfrog list starts 1, 8 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, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  19. 19.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?
  20. 20.A leapfrog list starts 2, 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): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  22. 22.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?
  23. 23.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?
  24. 24.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  26. 26.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  27. 27.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  28. 28.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?
  29. 29.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  34. 34.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?
  35. 35.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =

Answer key

  1. 143
  2. 374
  3. 143
  4. 396
  5. 484
  6. 495
  7. 374
  8. 396
  9. 286
  10. 1111
  11. 462
  12. 704
  13. 319
  14. 1199
  15. 935
  16. 1089
  17. 759
  18. 759
  19. 429
  20. 726
  21. 946
  22. 451
  23. 1144
  24. 1199
  25. 1034
  26. 869
  27. 880
  28. 704
  29. 759
  30. 1056
  31. 803
  32. 429
  33. 671
  34. 660
  35. 946
  36. 473
  37. 308
  38. 341
  39. 484
  40. 506

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