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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 298 · 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, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  2. 2.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  3. 3.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  10. 10.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?
  11. 11.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  15. 15.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  17. 17.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  20. 20.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?
  21. 21.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?
  22. 22.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  23. 23.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  24. 24.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  25. 25.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  26. 26.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?
  27. 27.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  28. 28.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  29. 29.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  34. 34.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  35. 35.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  36. 36.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  37. 37.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?
  38. 38.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 1232
  2. 759
  3. 1177
  4. 198
  5. 484
  6. 143
  7. 1144
  8. 143
  9. 473
  10. 671
  11. 671
  12. 924
  13. 517
  14. 979
  15. 594
  16. 506
  17. 1199
  18. 143
  19. 605
  20. 781
  21. 308
  22. 913
  23. 638
  24. 649
  25. 957
  26. 583
  27. 517
  28. 1056
  29. 253
  30. 704
  31. 616
  32. 715
  33. 308
  34. 561
  35. 1122
  36. 968
  37. 1012
  38. 869
  39. 495
  40. 1111

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