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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 762 · 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  2. 2.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  3. 3.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  4. 4.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?
  5. 5.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  6. 6.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  7. 7.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  8. 8.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.A leapfrog list starts 1, 9 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): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  15. 15.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  20. 20.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  21. 21.A leapfrog list starts 4, 4 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): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  25. 25.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?
  26. 26.A leapfrog list starts 5, 4 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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  28. 28.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  30. 30.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  31. 31.A leapfrog list starts 3, 7 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, 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 3, 9 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 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  36. 36.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?
  37. 37.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  39. 39.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  40. 40.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1056
  2. 858
  3. 671
  4. 682
  5. 869
  6. 1089
  7. 253
  8. 473
  9. 198
  10. 374
  11. 902
  12. 143
  13. 847
  14. 495
  15. 770
  16. 1122
  17. 1034
  18. 660
  19. 583
  20. 363
  21. 572
  22. 759
  23. 858
  24. 737
  25. 814
  26. 627
  27. 517
  28. 671
  29. 726
  30. 814
  31. 781
  32. 561
  33. 957
  34. 506
  35. 1012
  36. 583
  37. 726
  38. 341
  39. 451
  40. 418

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