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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 230 · 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 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  4. 4.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  5. 5.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  8. 8.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  15. 15.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  16. 16.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  17. 17.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  19. 19.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  20. 20.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  21. 21.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  22. 22.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?
  23. 23.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  24. 24.A leapfrog list starts 7, 9 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, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  28. 28.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?
  29. 29.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?
  30. 30.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  35. 35.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  36. 36.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  38. 38.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 759
  2. 880
  3. 1023
  4. 605
  5. 1122
  6. 253
  7. 517
  8. 561
  9. 583
  10. 407
  11. 286
  12. 605
  13. 396
  14. 616
  15. 825
  16. 880
  17. 638
  18. 1199
  19. 429
  20. 891
  21. 913
  22. 517
  23. 924
  24. 1177
  25. 946
  26. 913
  27. 583
  28. 1034
  29. 638
  30. 616
  31. 682
  32. 528
  33. 649
  34. 858
  35. 319
  36. 770
  37. 803
  38. 231
  39. 660
  40. 682

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