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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 791 · 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, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  2. 2.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?
  3. 3.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  4. 4.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  5. 5.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?
  6. 6.A leapfrog list starts 5, 4 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): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  8. 8.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?
  9. 9.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  11. 11.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  12. 12.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  13. 13.A leapfrog list starts 7, 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 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  15. 15.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?
  16. 16.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  19. 19.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  20. 20.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  21. 21.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?
  22. 22.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?
  23. 23.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  24. 24.A leapfrog list starts 3, 7 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): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  27. 27.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  28. 28.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  29. 29.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  30. 30.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  31. 31.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?
  32. 32.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  33. 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  35. 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 9, 2 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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 583
  2. 880
  3. 616
  4. 1287
  5. 484
  6. 627
  7. 913
  8. 396
  9. 1001
  10. 517
  11. 1012
  12. 319
  13. 561
  14. 880
  15. 462
  16. 341
  17. 1287
  18. 748
  19. 726
  20. 781
  21. 891
  22. 418
  23. 341
  24. 781
  25. 627
  26. 1122
  27. 1122
  28. 462
  29. 198
  30. 979
  31. 286
  32. 594
  33. 1111
  34. 451
  35. 231
  36. 858
  37. 1023
  38. 671
  39. 550
  40. 1177

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