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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 286 · 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.

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  1. 1.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?
  2. 2.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  8. 8.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 5, 2 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 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  13. 13.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?
  14. 14.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  15. 15.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  16. 16.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  19. 19.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  20. 20.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  22. 22.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  24. 24.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  25. 25.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  26. 26.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  27. 27.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  28. 28.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  30. 30.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  31. 31.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  32. 32.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?
  33. 33.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  37. 37.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?
  38. 38.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  39. 39.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  40. 40.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =

Answer key

  1. 143
  2. 561
  3. 583
  4. 649
  5. 902
  6. 704
  7. 858
  8. 1012
  9. 1056
  10. 451
  11. 495
  12. 583
  13. 913
  14. 759
  15. 913
  16. 902
  17. 1122
  18. 594
  19. 319
  20. 253
  21. 1232
  22. 715
  23. 1012
  24. 572
  25. 836
  26. 1111
  27. 781
  28. 770
  29. 616
  30. 979
  31. 407
  32. 341
  33. 583
  34. 979
  35. 1122
  36. 429
  37. 451
  38. 825
  39. 605
  40. 902

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