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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 291 · 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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  4. 4.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  9. 9.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?
  10. 10.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?
  11. 11.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  12. 12.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  13. 13.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  16. 16.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  17. 17.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  18. 18.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  20. 20.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  21. 21.A leapfrog list starts 6, 5 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.A leapfrog list starts 8, 3 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, 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): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  28. 28.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?
  29. 29.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  30. 30.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  32. 32.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  33. 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  34. 34.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?
  35. 35.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  36. 36.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?
  37. 37.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  38. 38.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?
  39. 39.A leapfrog list starts 4, 2 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?

Answer key

  1. 1089
  2. 880
  3. 198
  4. 429
  5. 671
  6. 869
  7. 1067
  8. 671
  9. 583
  10. 1111
  11. 1199
  12. 1056
  13. 957
  14. 231
  15. 1111
  16. 902
  17. 814
  18. 319
  19. 1001
  20. 825
  21. 770
  22. 638
  23. 418
  24. 517
  25. 704
  26. 627
  27. 1232
  28. 484
  29. 231
  30. 1144
  31. 737
  32. 891
  33. 1111
  34. 803
  35. 1144
  36. 495
  37. 726
  38. 561
  39. 396
  40. 781

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