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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 519 · 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. 2.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  4. 4.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?
  5. 5.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  6. 6.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  7. 7.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?
  8. 8.A leapfrog list starts 3, 6 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 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  12. 12.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?
  13. 13.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  14. 14.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?
  15. 15.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  16. 16.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  18. 18.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  19. 19.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  20. 20.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  21. 21.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  22. 22.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?
  23. 23.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  26. 26.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?
  27. 27.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  31. 31.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  32. 32.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  35. 35.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  36. 36.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  37. 37.A leapfrog list starts 9, 3 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): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  39. 39.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =

Answer key

  1. 473
  2. 198
  3. 528
  4. 704
  5. 572
  6. 913
  7. 759
  8. 693
  9. 726
  10. 418
  11. 715
  12. 858
  13. 946
  14. 605
  15. 814
  16. 803
  17. 286
  18. 550
  19. 374
  20. 792
  21. 484
  22. 616
  23. 616
  24. 847
  25. 451
  26. 770
  27. 1177
  28. 748
  29. 462
  30. 583
  31. 528
  32. 396
  33. 869
  34. 693
  35. 561
  36. 671
  37. 759
  38. 946
  39. 902
  40. 517

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