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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 328 · 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.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  4. 4.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?
  5. 5.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  7. 7.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  8. 8.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  12. 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  13. 13.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?
  14. 14.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  16. 16.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  24. 24.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  25. 25.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  27. 27.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?
  28. 28.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  29. 29.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  34. 34.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?
  35. 35.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  37. 37.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?
  38. 38.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  39. 39.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =

Answer key

  1. 143
  2. 396
  3. 594
  4. 968
  5. 253
  6. 1287
  7. 231
  8. 583
  9. 880
  10. 484
  11. 715
  12. 473
  13. 682
  14. 726
  15. 473
  16. 528
  17. 341
  18. 286
  19. 583
  20. 759
  21. 286
  22. 924
  23. 561
  24. 682
  25. 429
  26. 902
  27. 814
  28. 341
  29. 638
  30. 605
  31. 891
  32. 803
  33. 396
  34. 583
  35. 1199
  36. 528
  37. 495
  38. 1056
  39. 858
  40. 1199

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