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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 73 · 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): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  7. 7.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  8. 8.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  9. 9.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  10. 10.A leapfrog list starts 4, 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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  12. 12.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  13. 13.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?
  14. 14.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  15. 15.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?
  16. 16.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  17. 17.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?
  18. 18.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?
  19. 19.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  24. 24.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?
  25. 25.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  31. 31.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  32. 32.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?
  33. 33.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  35. 35.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  36. 36.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?
  37. 37.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?
  38. 38.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?

Answer key

  1. 671
  2. 198
  3. 913
  4. 1122
  5. 495
  6. 935
  7. 1122
  8. 407
  9. 451
  10. 1012
  11. 550
  12. 682
  13. 583
  14. 836
  15. 737
  16. 638
  17. 572
  18. 968
  19. 374
  20. 924
  21. 968
  22. 847
  23. 484
  24. 627
  25. 1067
  26. 462
  27. 539
  28. 627
  29. 539
  30. 616
  31. 231
  32. 473
  33. 858
  34. 1067
  35. 286
  36. 649
  37. 429
  38. 396
  39. 935
  40. 924

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