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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 265 · 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 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  2. 2.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?
  3. 3.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  6. 6.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  7. 7.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  8. 8.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?
  9. 9.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  10. 10.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?
  11. 11.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  12. 12.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  13. 13.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  14. 14.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?
  15. 15.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  21. 21.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  23. 23.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  24. 24.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?
  25. 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  26. 26.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?
  27. 27.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  28. 28.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  30. 30.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  31. 31.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  32. 32.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?
  33. 33.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  39. 39.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?
  40. 40.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =

Answer key

  1. 583
  2. 363
  3. 1287
  4. 880
  5. 682
  6. 374
  7. 363
  8. 1034
  9. 902
  10. 1001
  11. 429
  12. 693
  13. 913
  14. 759
  15. 1177
  16. 231
  17. 979
  18. 1144
  19. 561
  20. 638
  21. 198
  22. 671
  23. 704
  24. 495
  25. 726
  26. 616
  27. 1111
  28. 583
  29. 495
  30. 671
  31. 814
  32. 1144
  33. 506
  34. 198
  35. 517
  36. 869
  37. 1089
  38. 605
  39. 374
  40. 341

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