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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 564 · 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. 1.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  2. 2.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?
  3. 3.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?
  4. 4.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  5. 5.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  10. 10.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  11. 11.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?
  12. 12.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  13. 13.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  14. 14.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  16. 16.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?
  17. 17.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  18. 18.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?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  21. 21.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  22. 22.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?
  23. 23.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  25. 25.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  26. 26.A leapfrog list starts 3, 5 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 2, 1 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 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  30. 30.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  33. 33.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?

Answer key

  1. 1122
  2. 781
  3. 561
  4. 583
  5. 462
  6. 935
  7. 979
  8. 869
  9. 484
  10. 1034
  11. 1012
  12. 792
  13. 814
  14. 946
  15. 583
  16. 759
  17. 693
  18. 198
  19. 968
  20. 484
  21. 143
  22. 1056
  23. 319
  24. 726
  25. 407
  26. 605
  27. 198
  28. 759
  29. 847
  30. 1199
  31. 308
  32. 847
  33. 594
  34. 583
  35. 902
  36. 638
  37. 484
  38. 374
  39. 792
  40. 253

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