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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 556 · 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. 1.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  2. 2.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.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?
  7. 7.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  8. 8.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  10. 10.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?
  11. 11.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?
  12. 12.A leapfrog list starts 9, 1 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 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  18. 18.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?
  19. 19.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  21. 21.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  31. 31.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  32. 32.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?
  33. 33.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  34. 34.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  36. 36.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?
  37. 37.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?
  38. 38.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  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.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?

Answer key

  1. 286
  2. 913
  3. 781
  4. 792
  5. 572
  6. 231
  7. 682
  8. 968
  9. 407
  10. 517
  11. 561
  12. 583
  13. 869
  14. 605
  15. 517
  16. 374
  17. 319
  18. 561
  19. 649
  20. 1034
  21. 1287
  22. 759
  23. 847
  24. 1056
  25. 374
  26. 473
  27. 935
  28. 726
  29. 616
  30. 1067
  31. 143
  32. 418
  33. 605
  34. 506
  35. 550
  36. 363
  37. 550
  38. 572
  39. 858
  40. 1034

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