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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 331 · 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  2. 2.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  3. 3.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  5. 5.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  6. 6.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  7. 7.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  8. 8.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  9. 9.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  10. 10.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  17. 17.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 3, 9 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, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  21. 21.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  23. 23.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?
  24. 24.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  30. 30.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  31. 31.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?
  32. 32.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?
  33. 33.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  34. 34.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  36. 36.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  37. 37.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  38. 38.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?

Answer key

  1. 1034
  2. 902
  3. 583
  4. 891
  5. 957
  6. 363
  7. 517
  8. 473
  9. 594
  10. 814
  11. 858
  12. 748
  13. 143
  14. 583
  15. 847
  16. 462
  17. 198
  18. 957
  19. 462
  20. 759
  21. 1067
  22. 198
  23. 902
  24. 880
  25. 1056
  26. 506
  27. 319
  28. 484
  29. 1012
  30. 1232
  31. 605
  32. 781
  33. 825
  34. 693
  35. 605
  36. 704
  37. 616
  38. 429
  39. 517
  40. 1089

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