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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 912 · 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. 1.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  2. 2.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?
  3. 3.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  6. 6.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?
  7. 7.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  8. 8.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  9. 9.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?
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  16. 16.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  17. 17.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?
  18. 18.A leapfrog list starts 5, 9 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 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  21. 21.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  23. 23.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  25. 25.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?
  26. 26.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  28. 28.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?
  29. 29.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  33. 33.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  34. 34.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  35. 35.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  37. 37.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  38. 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  39. 39.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  40. 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =

Answer key

  1. 880
  2. 198
  3. 319
  4. 649
  5. 550
  6. 869
  7. 781
  8. 682
  9. 429
  10. 1122
  11. 704
  12. 737
  13. 759
  14. 407
  15. 1199
  16. 396
  17. 462
  18. 1067
  19. 781
  20. 671
  21. 671
  22. 539
  23. 847
  24. 1232
  25. 231
  26. 759
  27. 902
  28. 792
  29. 671
  30. 506
  31. 517
  32. 396
  33. 506
  34. 671
  35. 605
  36. 1144
  37. 374
  38. 451
  39. 198
  40. 1056

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