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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 119 · 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, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  6. 6.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  7. 7.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  9. 9.A leapfrog list starts 4, 2 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, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  13. 13.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?
  14. 14.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  15. 15.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  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. 17.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  18. 18.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  20. 20.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?
  21. 21.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?
  22. 22.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  24. 24.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  27. 27.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  38. 38.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  39. 39.A leapfrog list starts 1, 2 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 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1023
  2. 605
  3. 418
  4. 1199
  5. 726
  6. 1111
  7. 704
  8. 462
  9. 396
  10. 583
  11. 693
  12. 1111
  13. 803
  14. 1122
  15. 704
  16. 1012
  17. 858
  18. 825
  19. 825
  20. 550
  21. 748
  22. 638
  23. 561
  24. 715
  25. 1001
  26. 803
  27. 363
  28. 1199
  29. 935
  30. 814
  31. 572
  32. 880
  33. 935
  34. 649
  35. 627
  36. 1034
  37. 572
  38. 649
  39. 231
  40. 693

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