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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 457 · 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.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?
  2. 2.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  7. 7.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  8. 8.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  9. 9.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  10. 10.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?
  11. 11.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  14. 14.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  15. 15.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?
  16. 16.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  17. 17.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  18. 18.A leapfrog list starts 1, 5 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 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  21. 21.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  22. 22.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  23. 23.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  24. 24.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?
  25. 25.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  29. 29.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?
  30. 30.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?
  31. 31.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  32. 32.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?
  33. 33.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  34. 34.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  35. 35.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  36. 36.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  37. 37.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  38. 38.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  39. 39.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?
  40. 40.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =

Answer key

  1. 451
  2. 253
  3. 396
  4. 319
  5. 528
  6. 1067
  7. 418
  8. 704
  9. 858
  10. 418
  11. 484
  12. 1144
  13. 1012
  14. 825
  15. 407
  16. 473
  17. 572
  18. 495
  19. 1023
  20. 748
  21. 1056
  22. 198
  23. 495
  24. 1067
  25. 418
  26. 407
  27. 825
  28. 1034
  29. 319
  30. 1034
  31. 836
  32. 517
  33. 880
  34. 847
  35. 649
  36. 374
  37. 1232
  38. 429
  39. 473
  40. 803

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