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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 645 · 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 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  4. 4.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  5. 5.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?
  6. 6.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  7. 7.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?
  8. 8.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  9. 9.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?
  10. 10.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  11. 11.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?
  12. 12.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  13. 13.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  14. 14.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  16. 16.A leapfrog list starts 5, 7 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, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  18. 18.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  19. 19.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?
  20. 20.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  24. 24.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.A leapfrog list starts 8, 2 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): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  31. 31.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?
  32. 32.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  38. 38.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  39. 39.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?
  40. 40.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =

Answer key

  1. 583
  2. 561
  3. 748
  4. 451
  5. 418
  6. 506
  7. 429
  8. 759
  9. 1199
  10. 979
  11. 770
  12. 231
  13. 902
  14. 286
  15. 1287
  16. 891
  17. 253
  18. 594
  19. 847
  20. 1177
  21. 660
  22. 198
  23. 616
  24. 1001
  25. 715
  26. 1067
  27. 583
  28. 880
  29. 616
  30. 363
  31. 693
  32. 759
  33. 341
  34. 1287
  35. 451
  36. 572
  37. 462
  38. 550
  39. 506
  40. 407

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