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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 38 · 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. 1.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  3. 3.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?
  4. 4.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  5. 5.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?
  6. 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  7. 7.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  8. 8.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?
  9. 9.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  11. 11.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?
  12. 12.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?
  13. 13.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  14. 14.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  17. 17.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  19. 19.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  20. 20.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?
  21. 21.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  27. 27.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  30. 30.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  31. 31.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  33. 33.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  34. 34.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  35. 35.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.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?
  38. 38.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  39. 39.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?
  40. 40.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =

Answer key

  1. 451
  2. 847
  3. 286
  4. 671
  5. 902
  6. 814
  7. 374
  8. 1287
  9. 1056
  10. 924
  11. 583
  12. 1177
  13. 913
  14. 869
  15. 968
  16. 374
  17. 737
  18. 847
  19. 891
  20. 143
  21. 1056
  22. 583
  23. 594
  24. 198
  25. 429
  26. 605
  27. 616
  28. 308
  29. 693
  30. 1144
  31. 979
  32. 924
  33. 495
  34. 407
  35. 451
  36. 825
  37. 781
  38. 198
  39. 561
  40. 462

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