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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 181 · 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  4. 4.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?
  5. 5.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  10. 10.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?
  11. 11.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  13. 13.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  14. 14.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?
  15. 15.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?
  16. 16.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  19. 19.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  20. 20.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  21. 21.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  22. 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  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. 30.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  31. 31.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  33. 33.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  34. 34.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  35. 35.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  36. 36.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  37. 37.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  38. 38.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  39. 39.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  40. 40.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =

Answer key

  1. 902
  2. 781
  3. 462
  4. 495
  5. 968
  6. 231
  7. 704
  8. 869
  9. 638
  10. 1144
  11. 638
  12. 1001
  13. 1067
  14. 451
  15. 198
  16. 880
  17. 473
  18. 759
  19. 759
  20. 979
  21. 847
  22. 231
  23. 682
  24. 704
  25. 517
  26. 671
  27. 143
  28. 880
  29. 1232
  30. 1056
  31. 1144
  32. 539
  33. 682
  34. 726
  35. 550
  36. 286
  37. 1177
  38. 946
  39. 1287
  40. 143

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