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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 250 · 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. 1.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  2. 2.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  5. 5.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  8. 8.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?
  9. 9.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?
  10. 10.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  16. 16.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  17. 17.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?
  18. 18.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  24. 24.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  26. 26.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  27. 27.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  28. 28.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?
  29. 29.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  30. 30.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?
  31. 31.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  33. 33.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  34. 34.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  35. 35.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  40. 40.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =

Answer key

  1. 847
  2. 891
  3. 946
  4. 627
  5. 1144
  6. 1012
  7. 1034
  8. 693
  9. 319
  10. 286
  11. 737
  12. 429
  13. 616
  14. 143
  15. 803
  16. 924
  17. 550
  18. 891
  19. 627
  20. 605
  21. 143
  22. 693
  23. 671
  24. 374
  25. 616
  26. 1056
  27. 484
  28. 462
  29. 506
  30. 484
  31. 1001
  32. 231
  33. 704
  34. 1089
  35. 1177
  36. 473
  37. 539
  38. 781
  39. 979
  40. 748

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