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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 116 · 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 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  2. 2.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  5. 5.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  6. 6.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  7. 7.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  14. 14.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  15. 15.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  17. 17.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?
  18. 18.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  19. 19.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  20. 20.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  21. 21.A leapfrog list starts 6, 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): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  23. 23.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  25. 25.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  30. 30.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  31. 31.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  32. 32.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  33. 33.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  38. 38.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?

Answer key

  1. 429
  2. 693
  3. 1023
  4. 880
  5. 1232
  6. 704
  7. 759
  8. 814
  9. 143
  10. 374
  11. 363
  12. 462
  13. 792
  14. 748
  15. 737
  16. 759
  17. 825
  18. 847
  19. 231
  20. 880
  21. 1122
  22. 759
  23. 1056
  24. 1067
  25. 231
  26. 451
  27. 737
  28. 957
  29. 583
  30. 814
  31. 308
  32. 407
  33. 924
  34. 429
  35. 968
  36. 869
  37. 528
  38. 341
  39. 319
  40. 836

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