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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 975 · 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. 1.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  2. 2.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  4. 4.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  5. 5.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  8. 8.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  9. 9.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  12. 12.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  13. 13.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?
  14. 14.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?
  15. 15.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  17. 17.A leapfrog list starts 6, 3 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 4, 5 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 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  21. 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  22. 22.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?
  23. 23.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  24. 24.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?
  25. 25.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  26. 26.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  28. 28.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  29. 29.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  31. 31.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?
  32. 32.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  34. 34.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  35. 35.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?
  36. 36.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  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.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.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?
  40. 40.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?

Answer key

  1. 1177
  2. 660
  3. 550
  4. 484
  5. 550
  6. 902
  7. 407
  8. 198
  9. 429
  10. 253
  11. 649
  12. 814
  13. 814
  14. 682
  15. 704
  16. 825
  17. 594
  18. 660
  19. 1232
  20. 583
  21. 605
  22. 1012
  23. 1023
  24. 858
  25. 902
  26. 847
  27. 253
  28. 979
  29. 715
  30. 726
  31. 484
  32. 1067
  33. 429
  34. 1001
  35. 462
  36. 451
  37. 803
  38. 704
  39. 198
  40. 770

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