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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 779 · 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  4. 4.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  6. 6.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  12. 12.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  13. 13.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?
  14. 14.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?
  15. 15.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  17. 17.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  18. 18.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?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  28. 28.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?
  29. 29.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  30. 30.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?
  31. 31.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  32. 32.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  33. 33.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  34. 34.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  36. 36.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  37. 37.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  38. 38.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.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?
  40. 40.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?

Answer key

  1. 781
  2. 429
  3. 957
  4. 638
  5. 858
  6. 605
  7. 924
  8. 1056
  9. 528
  10. 572
  11. 1144
  12. 198
  13. 1089
  14. 484
  15. 968
  16. 1001
  17. 869
  18. 484
  19. 495
  20. 1287
  21. 847
  22. 561
  23. 319
  24. 594
  25. 814
  26. 693
  27. 572
  28. 715
  29. 583
  30. 341
  31. 781
  32. 341
  33. 561
  34. 946
  35. 847
  36. 462
  37. 902
  38. 660
  39. 231
  40. 605

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