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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 109 · 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. 1.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  2. 2.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?
  3. 3.A leapfrog list starts 9, 5 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, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  7. 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  9. 9.A leapfrog list starts 9, 7 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 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  13. 13.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?
  14. 14.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  15. 15.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?
  16. 16.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  17. 17.A leapfrog list starts 5, 8 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 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  20. 20.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  22. 22.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  24. 24.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.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?
  26. 26.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  27. 27.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  28. 28.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  29. 29.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  31. 31.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?
  32. 32.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?
  33. 33.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  34. 34.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  39. 39.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?
  40. 40.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =

Answer key

  1. 561
  2. 671
  3. 935
  4. 407
  5. 341
  6. 253
  7. 1111
  8. 506
  9. 1111
  10. 693
  11. 319
  12. 1089
  13. 880
  14. 363
  15. 429
  16. 407
  17. 979
  18. 418
  19. 836
  20. 792
  21. 583
  22. 1144
  23. 627
  24. 803
  25. 319
  26. 528
  27. 704
  28. 759
  29. 627
  30. 770
  31. 231
  32. 429
  33. 451
  34. 1232
  35. 484
  36. 572
  37. 341
  38. 638
  39. 1232
  40. 605

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