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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 474 · 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): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  2. 2.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  3. 3.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?
  4. 4.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  7. 7.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?
  8. 8.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  9. 9.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  10. 10.A leapfrog list starts 3, 4 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 4, 4 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 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  15. 15.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  16. 16.A leapfrog list starts 8, 6 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): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  18. 18.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?
  19. 19.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  20. 20.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.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?
  25. 25.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  26. 26.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?
  27. 27.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  29. 29.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  30. 30.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?
  31. 31.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  34. 34.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  35. 35.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?
  36. 36.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  37. 37.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  38. 38.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  39. 39.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?
  40. 40.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =

Answer key

  1. 473
  2. 253
  3. 407
  4. 891
  5. 451
  6. 1089
  7. 583
  8. 594
  9. 704
  10. 517
  11. 572
  12. 1232
  13. 319
  14. 572
  15. 1199
  16. 968
  17. 495
  18. 825
  19. 198
  20. 583
  21. 1056
  22. 550
  23. 1144
  24. 814
  25. 429
  26. 539
  27. 924
  28. 462
  29. 451
  30. 583
  31. 836
  32. 319
  33. 814
  34. 308
  35. 1023
  36. 1067
  37. 858
  38. 770
  39. 1111
  40. 495

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