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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 788 · 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.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?
  2. 2.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  9. 9.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  10. 10.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  11. 11.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  12. 12.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  13. 13.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  15. 15.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  16. 16.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  17. 17.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  18. 18.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  20. 20.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  21. 21.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  22. 22.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  28. 28.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  29. 29.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  30. 30.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  32. 32.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  33. 33.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?
  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.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?
  36. 36.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?
  37. 37.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?
  38. 38.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  39. 39.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  40. 40.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =

Answer key

  1. 341
  2. 517
  3. 495
  4. 418
  5. 484
  6. 231
  7. 792
  8. 143
  9. 825
  10. 671
  11. 319
  12. 616
  13. 671
  14. 308
  15. 759
  16. 495
  17. 550
  18. 253
  19. 792
  20. 671
  21. 946
  22. 759
  23. 605
  24. 1122
  25. 484
  26. 968
  27. 583
  28. 418
  29. 847
  30. 1122
  31. 759
  32. 561
  33. 880
  34. 770
  35. 286
  36. 561
  37. 913
  38. 583
  39. 781
  40. 869

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