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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 292 · 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): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  4. 4.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  5. 5.A leapfrog list starts 3, 4 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): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  7. 7.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  8. 8.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  9. 9.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  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.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?
  12. 12.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?
  13. 13.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  14. 14.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?
  15. 15.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  19. 19.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?
  20. 20.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  26. 26.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?
  27. 27.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?
  28. 28.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  29. 29.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  30. 30.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  35. 35.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?
  36. 36.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  37. 37.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  38. 38.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  39. 39.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  40. 40.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 484
  2. 858
  3. 759
  4. 418
  5. 517
  6. 737
  7. 858
  8. 946
  9. 198
  10. 924
  11. 484
  12. 880
  13. 968
  14. 451
  15. 1012
  16. 363
  17. 671
  18. 231
  19. 1177
  20. 693
  21. 473
  22. 1122
  23. 539
  24. 671
  25. 341
  26. 1034
  27. 847
  28. 495
  29. 792
  30. 891
  31. 715
  32. 759
  33. 253
  34. 671
  35. 550
  36. 407
  37. 902
  38. 671
  39. 803
  40. 495

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