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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 179 · 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. 1.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  3. 3.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?
  4. 4.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  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.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?
  9. 9.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  10. 10.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?
  11. 11.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  12. 12.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  13. 13.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?
  14. 14.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?
  15. 15.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  16. 16.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  17. 17.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  22. 22.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  23. 23.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  26. 26.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?
  27. 27.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  30. 30.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  31. 31.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  32. 32.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  33. 33.A leapfrog list starts 3, 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): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  35. 35.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  38. 38.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?
  39. 39.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  40. 40.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?

Answer key

  1. 561
  2. 495
  3. 429
  4. 495
  5. 1056
  6. 484
  7. 671
  8. 506
  9. 979
  10. 627
  11. 484
  12. 825
  13. 396
  14. 880
  15. 781
  16. 407
  17. 407
  18. 286
  19. 726
  20. 517
  21. 473
  22. 704
  23. 924
  24. 759
  25. 594
  26. 638
  27. 528
  28. 1122
  29. 759
  30. 770
  31. 935
  32. 341
  33. 605
  34. 770
  35. 1287
  36. 253
  37. 528
  38. 561
  39. 396
  40. 341

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