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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 233 · 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. 1.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  2. 2.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  4. 4.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  5. 5.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?
  6. 6.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  7. 7.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  9. 9.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?
  10. 10.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  11. 11.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  14. 14.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?
  15. 15.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  24. 24.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  25. 25.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  26. 26.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  27. 27.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  31. 31.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?
  32. 32.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  33. 33.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  35. 35.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  36. 36.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  38. 38.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =

Answer key

  1. 462
  2. 231
  3. 1012
  4. 869
  5. 704
  6. 308
  7. 253
  8. 1122
  9. 825
  10. 781
  11. 1287
  12. 572
  13. 253
  14. 473
  15. 748
  16. 429
  17. 517
  18. 671
  19. 561
  20. 781
  21. 1111
  22. 935
  23. 341
  24. 891
  25. 1034
  26. 429
  27. 880
  28. 616
  29. 770
  30. 682
  31. 539
  32. 946
  33. 561
  34. 286
  35. 660
  36. 946
  37. 924
  38. 341
  39. 143
  40. 902

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