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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 406 · 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.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  4. 4.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  6. 6.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?
  7. 7.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  8. 8.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?
  9. 9.A leapfrog list starts 8, 8 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 9, 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): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  12. 12.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?
  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. 14.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  15. 15.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.A leapfrog list starts 5, 3 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): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 7, 9 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 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  23. 23.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?
  24. 24.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  25. 25.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?
  26. 26.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  27. 27.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?
  28. 28.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?
  29. 29.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  32. 32.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  33. 33.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  36. 36.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?
  37. 37.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?
  38. 38.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  39. 39.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  40. 40.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?

Answer key

  1. 308
  2. 957
  3. 1177
  4. 880
  5. 484
  6. 319
  7. 319
  8. 429
  9. 1144
  10. 1287
  11. 891
  12. 1023
  13. 759
  14. 825
  15. 451
  16. 539
  17. 363
  18. 649
  19. 583
  20. 1177
  21. 319
  22. 649
  23. 1232
  24. 957
  25. 627
  26. 792
  27. 506
  28. 1232
  29. 880
  30. 407
  31. 946
  32. 979
  33. 660
  34. 473
  35. 143
  36. 638
  37. 473
  38. 1111
  39. 1144
  40. 902

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