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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 117 · 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. 1.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  2. 2.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?
  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. 4.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  5. 5.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?
  6. 6.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?
  7. 7.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  9. 9.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  10. 10.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?
  11. 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  15. 15.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  17. 17.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  21. 21.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  22. 22.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  23. 23.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?
  24. 24.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  26. 26.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  28. 28.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  29. 29.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?
  30. 30.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  34. 34.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?
  35. 35.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  36. 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  37. 37.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?
  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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  40. 40.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =

Answer key

  1. 231
  2. 253
  3. 1001
  4. 484
  5. 792
  6. 462
  7. 671
  8. 858
  9. 913
  10. 704
  11. 286
  12. 605
  13. 561
  14. 979
  15. 935
  16. 693
  17. 715
  18. 198
  19. 572
  20. 726
  21. 1199
  22. 946
  23. 759
  24. 484
  25. 1144
  26. 649
  27. 616
  28. 880
  29. 1144
  30. 143
  31. 803
  32. 286
  33. 198
  34. 517
  35. 319
  36. 308
  37. 341
  38. 341
  39. 869
  40. 495

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