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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 666 · 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 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  2. 2.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  3. 3.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?
  4. 4.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  5. 5.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?
  6. 6.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?
  7. 7.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  8. 8.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  9. 9.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?
  10. 10.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  11. 11.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  12. 12.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  13. 13.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  20. 20.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?
  21. 21.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?
  22. 22.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  23. 23.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?
  24. 24.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  27. 27.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?
  28. 28.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  30. 30.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  31. 31.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  32. 32.A leapfrog list starts 2, 4 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 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  35. 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  36. 36.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?
  37. 37.A leapfrog list starts 1, 6 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 4, 8 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 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =

Answer key

  1. 1023
  2. 286
  3. 693
  4. 341
  5. 341
  6. 143
  7. 1056
  8. 825
  9. 473
  10. 374
  11. 473
  12. 1067
  13. 363
  14. 528
  15. 847
  16. 1287
  17. 759
  18. 792
  19. 561
  20. 649
  21. 374
  22. 484
  23. 869
  24. 814
  25. 671
  26. 649
  27. 616
  28. 847
  29. 572
  30. 517
  31. 902
  32. 462
  33. 1034
  34. 803
  35. 231
  36. 462
  37. 583
  38. 924
  39. 231
  40. 726

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