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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 662 · 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): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  5. 5.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  8. 8.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  10. 10.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?
  11. 11.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?
  12. 12.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  19. 19.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?
  20. 20.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?
  21. 21.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  22. 22.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  23. 23.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?
  24. 24.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  25. 25.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?
  26. 26.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  28. 28.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?
  29. 29.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  30. 30.A leapfrog list starts 3, 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): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  32. 32.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  33. 33.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?
  34. 34.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  35. 35.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?
  36. 36.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  37. 37.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  38. 38.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  39. 39.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?
  40. 40.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =

Answer key

  1. 1122
  2. 462
  3. 407
  4. 726
  5. 759
  6. 506
  7. 671
  8. 616
  9. 429
  10. 319
  11. 231
  12. 693
  13. 748
  14. 836
  15. 913
  16. 1122
  17. 737
  18. 704
  19. 660
  20. 451
  21. 814
  22. 495
  23. 803
  24. 737
  25. 836
  26. 1111
  27. 1001
  28. 429
  29. 979
  30. 869
  31. 770
  32. 781
  33. 935
  34. 671
  35. 1177
  36. 825
  37. 638
  38. 913
  39. 473
  40. 748

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