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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 468 · 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. 1.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  3. 3.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  6. 6.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?
  7. 7.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  8. 8.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  9. 9.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  11. 11.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?
  12. 12.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  13. 13.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  14. 14.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?
  15. 15.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?
  16. 16.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  17. 17.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  18. 18.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  19. 19.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  20. 20.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?
  21. 21.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  22. 22.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  23. 23.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?
  24. 24.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?
  25. 25.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  26. 26.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?
  27. 27.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?
  28. 28.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  30. 30.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  31. 31.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  32. 32.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?
  33. 33.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  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): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  36. 36.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?
  37. 37.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  40. 40.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =

Answer key

  1. 682
  2. 231
  3. 231
  4. 506
  5. 891
  6. 462
  7. 253
  8. 319
  9. 616
  10. 814
  11. 869
  12. 1089
  13. 627
  14. 583
  15. 759
  16. 814
  17. 1287
  18. 803
  19. 1144
  20. 913
  21. 539
  22. 407
  23. 561
  24. 1111
  25. 550
  26. 649
  27. 528
  28. 1067
  29. 946
  30. 847
  31. 759
  32. 1034
  33. 649
  34. 1287
  35. 484
  36. 198
  37. 286
  38. 462
  39. 616
  40. 418

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