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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 527 · 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. 1.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  3. 3.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  4. 4.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  5. 5.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?
  6. 6.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?
  7. 7.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  8. 8.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  13. 13.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  14. 14.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.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?
  17. 17.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  18. 18.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  20. 20.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  22. 22.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?
  23. 23.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  24. 24.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  25. 25.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  26. 26.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?
  27. 27.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?
  28. 28.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  32. 32.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?
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  35. 35.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  36. 36.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  37. 37.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?
  38. 38.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  40. 40.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =

Answer key

  1. 429
  2. 1232
  3. 1111
  4. 517
  5. 1034
  6. 341
  7. 748
  8. 979
  9. 231
  10. 374
  11. 759
  12. 583
  13. 363
  14. 1023
  15. 759
  16. 396
  17. 616
  18. 825
  19. 253
  20. 847
  21. 770
  22. 616
  23. 814
  24. 583
  25. 803
  26. 308
  27. 946
  28. 814
  29. 616
  30. 627
  31. 847
  32. 319
  33. 484
  34. 1144
  35. 506
  36. 198
  37. 913
  38. 1001
  39. 363
  40. 913

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