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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 883 · 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 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  3. 3.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  6. 6.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  7. 7.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  8. 8.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  11. 11.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  12. 12.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  13. 13.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?
  14. 14.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  15. 15.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  17. 17.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  23. 23.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  24. 24.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  25. 25.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?
  26. 26.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  27. 27.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  28. 28.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  30. 30.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  31. 31.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  32. 32.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?
  33. 33.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  34. 34.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  35. 35.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  37. 37.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?
  38. 38.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?
  39. 39.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?

Answer key

  1. 704
  2. 286
  3. 1089
  4. 847
  5. 429
  6. 495
  7. 231
  8. 451
  9. 770
  10. 649
  11. 704
  12. 374
  13. 572
  14. 1287
  15. 792
  16. 836
  17. 517
  18. 847
  19. 506
  20. 1122
  21. 814
  22. 550
  23. 198
  24. 979
  25. 671
  26. 583
  27. 1056
  28. 847
  29. 968
  30. 418
  31. 869
  32. 726
  33. 726
  34. 561
  35. 748
  36. 781
  37. 484
  38. 473
  39. 528
  40. 935

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