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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 493 · 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): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  2. 2.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  9. 9.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  10. 10.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?
  11. 11.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?
  12. 12.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  13. 13.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?
  14. 14.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?
  15. 15.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 4, 7 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 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  21. 21.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  22. 22.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  23. 23.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?
  24. 24.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  26. 26.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?
  27. 27.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  28. 28.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  29. 29.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?
  30. 30.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  31. 31.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  33. 33.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  34. 34.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  35. 35.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?
  36. 36.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  39. 39.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =

Answer key

  1. 836
  2. 473
  3. 286
  4. 1034
  5. 759
  6. 231
  7. 704
  8. 660
  9. 583
  10. 561
  11. 231
  12. 253
  13. 583
  14. 451
  15. 781
  16. 253
  17. 638
  18. 836
  19. 583
  20. 1067
  21. 341
  22. 638
  23. 308
  24. 726
  25. 539
  26. 429
  27. 979
  28. 759
  29. 913
  30. 363
  31. 495
  32. 1023
  33. 341
  34. 748
  35. 858
  36. 1111
  37. 671
  38. 759
  39. 1122
  40. 418

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