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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 731 · 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. 1.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  3. 3.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?
  4. 4.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  5. 5.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  6. 6.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?
  7. 7.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  8. 8.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  9. 9.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  10. 10.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.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?
  13. 13.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  14. 14.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?
  15. 15.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?
  16. 16.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  20. 20.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  22. 22.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?
  23. 23.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  24. 24.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  25. 25.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?
  26. 26.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.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?
  28. 28.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?
  29. 29.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  32. 32.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  37. 37.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?
  38. 38.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  39. 39.A leapfrog list starts 8, 6 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): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?

Answer key

  1. 682
  2. 671
  3. 528
  4. 1067
  5. 638
  6. 913
  7. 869
  8. 319
  9. 1177
  10. 1122
  11. 737
  12. 473
  13. 605
  14. 858
  15. 308
  16. 1089
  17. 781
  18. 792
  19. 704
  20. 495
  21. 363
  22. 341
  23. 737
  24. 429
  25. 583
  26. 1111
  27. 825
  28. 671
  29. 484
  30. 418
  31. 671
  32. 649
  33. 1034
  34. 1056
  35. 198
  36. 869
  37. 858
  38. 825
  39. 968
  40. 649

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