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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 641 · 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, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  8. 8.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  9. 9.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  10. 10.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  11. 11.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  12. 12.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?
  13. 13.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?
  14. 14.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  15. 15.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  17. 17.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  18. 18.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?
  19. 19.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  20. 20.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  21. 21.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?
  22. 22.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  24. 24.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?
  25. 25.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.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?
  28. 28.A leapfrog list starts 6, 8 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.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?
  31. 31.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  32. 32.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  33. 33.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  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 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  39. 39.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.A leapfrog list starts 2, 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. 1056
  2. 363
  3. 484
  4. 1089
  5. 495
  6. 627
  7. 869
  8. 770
  9. 946
  10. 693
  11. 341
  12. 814
  13. 638
  14. 979
  15. 869
  16. 605
  17. 1232
  18. 924
  19. 1177
  20. 407
  21. 847
  22. 935
  23. 143
  24. 473
  25. 231
  26. 143
  27. 671
  28. 1034
  29. 231
  30. 726
  31. 396
  32. 583
  33. 286
  34. 429
  35. 759
  36. 495
  37. 902
  38. 462
  39. 858
  40. 550

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