Question

4~9这六个数可以组成几个四位数？

Answer 1

6*5*4*3=360(个) 4567,4576,4657,4675,4756,4765 5674,5647,5476,5467,5746,5764 6457,6475,6574,6547,6745,6754 7456,7465,7546,7564,7654,7645 4568,4586,4685,4658,4856,4865 5684,5648,5486,5468,5846,5864 6458,6485,6584,6548,6854,6845 8456,8465,8564,8546,8654,8645 4569,4596,4695,4659,4965,4956 5469,5496,5694,5649,5964,5946 6459,6495,6594,6549,6945,6954 9456,9465,9564,9546,9654,9645 4578,4587,4785,4758,4857,4875 5478,5487,5748,5784,5874,5847 7458,7485,7854,7845,7584,7548 8745,8754,8475,8457,8547,8574 4579,4597,4759,4795,4957,4975 5794,5749,5479,5497,5947,5947 7459,7495,7549,7594,7945,7954 9457,9475,9547,9574,9745,9754 4589,4598,4895,4859,4958,4985 5489,5498,5894,5849,5984,5948 8459,8495,8549,8594,8945,8954 9854,9845,9485,9458,9584,9548 4678,4687,4786,4768,4876,4867 6478,6487,6748,6784,6874,6847 7468,7486,7684,7648,7846,7864 8746,8764,8467,8476,8647,8674 4679,4697,4796,4769,4976,4967 6479,6497,6794,6749,6974,6947 7469,7496,7694,7649,7964,7946 9746,9764,9476,9467,9647,9674 4689,4698,4896,4869,4986,4968 6489,6498,6849,6894,6984,6948 8469,8496,8694,8649,8964,8946 9846,9864,9486,9468,9684,9648 4789,4798,4987,4978,4879,4897 7489,7498,7849,7894,7984,7948 8479,8497,8974,8947,8794,8749 9874,9847,9748,9784,9478,9487 5678,5687,5876,5867,5786,5768 7568,7586,7658,7685,7856,7865 6785,6758,6587,6578,6875,6857 8756,8765,8567,8576,8657,8675 5679,5697,5967,5976,5769,5796 6759,6795,6957,6975,6579,6597 7569,7596,7659,7695,7956,7965 9756,9765,9567,9576,9675,9657 5689,5698,5968,5986,5896,5869 6895,6859,6958,6985,6589,6598 8956,8965,8596,8569,8659,8695 9568,9586,9658,9685,9856,9865 5789,5798,5987,5978,5879,5897 7859,7895,7985,7958,7589,7598 8759,8795,8579,8597,8957,8975 9875,9857,9578,9587,9785,9758 6789,6798,6897,6879,6987,6978 7896,7869,7968,7986,7689,7698 8796,8769,8967,8976,8679,8697 9876,9867,9687,9678,9786,9768