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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 985 · 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, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  2. 2.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  9. 9.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  10. 10.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  11. 11.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  13. 13.A leapfrog list starts 6, 4 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. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  17. 17.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  18. 18.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  25. 25.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  26. 26.A leapfrog list starts 5, 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): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  28. 28.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  34. 34.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  35. 35.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  36. 36.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  37. 37.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?
  38. 38.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?
  39. 39.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  40. 40.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?

Answer key

  1. 374
  2. 429
  3. 1012
  4. 825
  5. 341
  6. 638
  7. 506
  8. 759
  9. 1122
  10. 649
  11. 946
  12. 143
  13. 682
  14. 704
  15. 198
  16. 836
  17. 814
  18. 341
  19. 1177
  20. 693
  21. 517
  22. 649
  23. 968
  24. 143
  25. 517
  26. 539
  27. 1067
  28. 671
  29. 869
  30. 1034
  31. 583
  32. 1001
  33. 825
  34. 418
  35. 979
  36. 1089
  37. 583
  38. 451
  39. 308
  40. 495

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