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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 497 · 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.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  3. 3.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  4. 4.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  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.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?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  11. 11.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?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  14. 14.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?
  15. 15.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?
  16. 16.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  17. 17.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  19. 19.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  24. 24.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  25. 25.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  27. 27.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  28. 28.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?
  29. 29.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  30. 30.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  31. 31.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  33. 33.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?
  34. 34.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?
  35. 35.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  39. 39.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =

Answer key

  1. 968
  2. 462
  3. 770
  4. 572
  5. 803
  6. 462
  7. 539
  8. 429
  9. 924
  10. 737
  11. 759
  12. 143
  13. 968
  14. 946
  15. 660
  16. 671
  17. 902
  18. 1232
  19. 374
  20. 484
  21. 649
  22. 231
  23. 825
  24. 792
  25. 946
  26. 1177
  27. 473
  28. 682
  29. 396
  30. 704
  31. 671
  32. 979
  33. 737
  34. 407
  35. 1111
  36. 836
  37. 671
  38. 605
  39. 319
  40. 1232

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