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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 66 · 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. 1.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  4. 4.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  5. 5.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?
  6. 6.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?
  7. 7.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  9. 9.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?
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  12. 12.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 5, 3 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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  18. 18.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  19. 19.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  24. 24.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  25. 25.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  26. 26.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  29. 29.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  30. 30.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?
  31. 31.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  32. 32.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?
  33. 33.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  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. 35.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  36. 36.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?
  37. 37.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  39. 39.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?
  40. 40.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =

Answer key

  1. 583
  2. 671
  3. 506
  4. 715
  5. 561
  6. 880
  7. 847
  8. 660
  9. 429
  10. 308
  11. 737
  12. 396
  13. 847
  14. 539
  15. 550
  16. 671
  17. 407
  18. 979
  19. 957
  20. 1067
  21. 363
  22. 858
  23. 473
  24. 814
  25. 847
  26. 946
  27. 968
  28. 319
  29. 638
  30. 682
  31. 1122
  32. 616
  33. 550
  34. 451
  35. 1144
  36. 1111
  37. 473
  38. 649
  39. 902
  40. 682

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