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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 620 · 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. 1.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  2. 2.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?
  3. 3.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?
  4. 4.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  7. 7.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  8. 8.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?
  9. 9.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  10. 10.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?
  11. 11.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?
  12. 12.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  13. 13.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  19. 19.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  20. 20.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?
  21. 21.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  22. 22.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  23. 23.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  25. 25.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  26. 26.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  27. 27.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?
  28. 28.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  29. 29.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?
  30. 30.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  31. 31.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?
  32. 32.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?
  33. 33.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 5, 2 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, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 605
  2. 517
  3. 561
  4. 693
  5. 286
  6. 341
  7. 407
  8. 1034
  9. 649
  10. 605
  11. 583
  12. 253
  13. 704
  14. 429
  15. 484
  16. 539
  17. 671
  18. 759
  19. 363
  20. 616
  21. 616
  22. 726
  23. 1144
  24. 847
  25. 814
  26. 484
  27. 550
  28. 1111
  29. 484
  30. 803
  31. 495
  32. 715
  33. 506
  34. 759
  35. 935
  36. 924
  37. 825
  38. 1012
  39. 451
  40. 902

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