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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 767 · 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. 1.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  2. 2.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  3. 3.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  9. 9.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  10. 10.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  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. 12.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  13. 13.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  19. 19.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?
  20. 20.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.A leapfrog list starts 4, 6 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): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  28. 28.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  29. 29.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  30. 30.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?
  31. 31.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  33. 33.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  35. 35.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  37. 37.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?
  38. 38.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  39. 39.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?
  40. 40.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 935
  2. 1111
  3. 1144
  4. 1199
  5. 451
  6. 671
  7. 550
  8. 836
  9. 693
  10. 1023
  11. 484
  12. 803
  13. 792
  14. 539
  15. 143
  16. 1012
  17. 847
  18. 1287
  19. 1067
  20. 869
  21. 935
  22. 671
  23. 506
  24. 550
  25. 957
  26. 748
  27. 968
  28. 605
  29. 1122
  30. 803
  31. 638
  32. 1034
  33. 286
  34. 561
  35. 924
  36. 396
  37. 1122
  38. 473
  39. 462
  40. 770

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