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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 898 · 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.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?
  2. 2.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?
  3. 3.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  4. 4.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  5. 5.A leapfrog list starts 2, 3 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  7. 7.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  8. 8.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  9. 9.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  10. 10.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?
  11. 11.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?
  12. 12.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  16. 16.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  19. 19.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  20. 20.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  21. 21.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  22. 22.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?
  23. 23.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 6, 6 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 5, 6 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): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  28. 28.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  29. 29.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  34. 34.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  35. 35.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?
  36. 36.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  37. 37.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  38. 38.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  39. 39.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?
  40. 40.A leapfrog list starts 1, 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. 825
  2. 737
  3. 1067
  4. 1111
  5. 374
  6. 869
  7. 902
  8. 308
  9. 550
  10. 847
  11. 517
  12. 924
  13. 363
  14. 968
  15. 968
  16. 891
  17. 528
  18. 418
  19. 836
  20. 737
  21. 286
  22. 550
  23. 1056
  24. 803
  25. 858
  26. 803
  27. 198
  28. 792
  29. 1144
  30. 583
  31. 946
  32. 759
  33. 1199
  34. 374
  35. 341
  36. 396
  37. 517
  38. 143
  39. 1012
  40. 143

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