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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 484 · 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, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  6. 6.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?
  7. 7.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  8. 8.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?
  9. 9.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?
  10. 10.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  11. 11.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  12. 12.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?
  13. 13.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?
  14. 14.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  15. 15.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  16. 16.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  17. 17.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?
  18. 18.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?
  19. 19.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  22. 22.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?
  23. 23.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  24. 24.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?
  25. 25.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  26. 26.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  27. 27.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  33. 33.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  34. 34.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  36. 36.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?
  37. 37.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  38. 38.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?
  39. 39.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  40. 40.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 462
  2. 704
  3. 418
  4. 627
  5. 231
  6. 528
  7. 825
  8. 517
  9. 968
  10. 748
  11. 660
  12. 946
  13. 726
  14. 704
  15. 583
  16. 627
  17. 913
  18. 473
  19. 638
  20. 286
  21. 407
  22. 198
  23. 803
  24. 517
  25. 968
  26. 1034
  27. 847
  28. 792
  29. 803
  30. 957
  31. 759
  32. 374
  33. 506
  34. 561
  35. 583
  36. 1067
  37. 814
  38. 253
  39. 143
  40. 748

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