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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 949 · 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  2. 2.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  3. 3.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  4. 4.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  5. 5.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  6. 6.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  8. 8.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  9. 9.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?
  10. 10.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  13. 13.A leapfrog list starts 4, 5 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): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. 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 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  17. 17.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  19. 19.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?
  20. 20.A leapfrog list starts 2, 2 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 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  23. 23.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?
  24. 24.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  25. 25.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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. 29.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  30. 30.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  35. 35.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?
  36. 36.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?
  37. 37.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  38. 38.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  39. 39.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?

Answer key

  1. 143
  2. 528
  3. 484
  4. 550
  5. 462
  6. 913
  7. 957
  8. 781
  9. 451
  10. 638
  11. 979
  12. 1287
  13. 660
  14. 792
  15. 1177
  16. 143
  17. 1056
  18. 814
  19. 495
  20. 286
  21. 1012
  22. 825
  23. 451
  24. 451
  25. 550
  26. 517
  27. 231
  28. 583
  29. 825
  30. 363
  31. 671
  32. 616
  33. 759
  34. 605
  35. 198
  36. 539
  37. 616
  38. 946
  39. 308
  40. 627

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