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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 515 · 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. 1.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  5. 5.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  6. 6.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  7. 7.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?
  8. 8.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  9. 9.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?
  10. 10.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?
  11. 11.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  12. 12.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?
  13. 13.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  14. 14.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  15. 15.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  17. 17.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?
  18. 18.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?
  19. 19.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  20. 20.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?
  21. 21.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?
  22. 22.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  23. 23.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?
  24. 24.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  25. 25.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?
  26. 26.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?
  27. 27.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  28. 28.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?
  29. 29.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  30. 30.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?
  31. 31.A leapfrog list starts 4, 7 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 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  34. 34.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  36. 36.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?
  37. 37.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?
  38. 38.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  39. 39.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  40. 40.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 847
  2. 143
  3. 913
  4. 968
  5. 704
  6. 748
  7. 341
  8. 1001
  9. 506
  10. 715
  11. 913
  12. 924
  13. 902
  14. 550
  15. 957
  16. 770
  17. 462
  18. 473
  19. 1144
  20. 792
  21. 847
  22. 737
  23. 1056
  24. 638
  25. 407
  26. 968
  27. 660
  28. 451
  29. 363
  30. 319
  31. 836
  32. 561
  33. 451
  34. 671
  35. 363
  36. 550
  37. 396
  38. 627
  39. 319
  40. 198

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