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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 569 · 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 5, 5 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.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.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?
  5. 5.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  6. 6.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?
  7. 7.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  9. 9.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  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. 14.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  15. 15.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  16. 16.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  17. 17.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  18. 18.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  20. 20.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  21. 21.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.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?
  24. 24.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  25. 25.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  27. 27.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  33. 33.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  34. 34.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  35. 35.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.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?
  40. 40.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 715
  2. 462
  3. 825
  4. 968
  5. 429
  6. 495
  7. 913
  8. 1089
  9. 231
  10. 1111
  11. 858
  12. 902
  13. 968
  14. 1056
  15. 682
  16. 363
  17. 1122
  18. 583
  19. 374
  20. 924
  21. 484
  22. 946
  23. 363
  24. 770
  25. 649
  26. 1144
  27. 737
  28. 1232
  29. 726
  30. 737
  31. 451
  32. 671
  33. 759
  34. 319
  35. 396
  36. 1177
  37. 374
  38. 484
  39. 627
  40. 495

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