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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 737 · 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. 1.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  3. 3.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  4. 4.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?
  5. 5.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  6. 6.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  10. 10.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  11. 11.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?
  12. 12.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  13. 13.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  14. 14.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?
  15. 15.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?
  16. 16.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  17. 17.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  18. 18.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?
  19. 19.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  20. 20.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?
  21. 21.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  22. 22.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?
  23. 23.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  24. 24.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  25. 25.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?
  26. 26.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?
  27. 27.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  28. 28.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  29. 29.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  31. 31.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?
  32. 32.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  33. 33.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  34. 34.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?
  35. 35.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?
  36. 36.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.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?
  39. 39.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  40. 40.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =

Answer key

  1. 473
  2. 913
  3. 880
  4. 561
  5. 847
  6. 726
  7. 429
  8. 539
  9. 253
  10. 506
  11. 484
  12. 891
  13. 792
  14. 770
  15. 572
  16. 638
  17. 396
  18. 506
  19. 319
  20. 517
  21. 671
  22. 517
  23. 737
  24. 143
  25. 319
  26. 748
  27. 1012
  28. 1001
  29. 759
  30. 396
  31. 957
  32. 627
  33. 484
  34. 638
  35. 759
  36. 253
  37. 1056
  38. 143
  39. 561
  40. 671

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