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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 460 · 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  4. 4.A leapfrog list starts 9, 9 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): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  6. 6.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?
  7. 7.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  8. 8.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  12. 12.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  15. 15.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?
  16. 16.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  18. 18.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  21. 21.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  22. 22.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?
  23. 23.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  25. 25.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  28. 28.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  31. 31.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  33. 33.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?
  34. 34.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  35. 35.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?
  36. 36.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  37. 37.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  38. 38.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  39. 39.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?

Answer key

  1. 143
  2. 803
  3. 396
  4. 1287
  5. 616
  6. 946
  7. 462
  8. 847
  9. 847
  10. 484
  11. 781
  12. 363
  13. 880
  14. 748
  15. 286
  16. 891
  17. 374
  18. 748
  19. 374
  20. 671
  21. 1023
  22. 1177
  23. 671
  24. 946
  25. 1089
  26. 902
  27. 792
  28. 418
  29. 605
  30. 682
  31. 363
  32. 671
  33. 1177
  34. 814
  35. 286
  36. 671
  37. 704
  38. 726
  39. 737
  40. 396

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