9 8 7 6 5 4 3 2 1=1 任意填写 “加减乘除"

无解。
所有的280种情况结果都不为1
9/8*7-6+54321 = 54322.875
9*8/7-6+54321 = 54325.28571
9/8-7*6+54321 = 54280.125
9*8-7/6+54321 = 54391.83333
9/8*7-65+4321 = 4263.875
9*8/7-65+4321 = 4266.285714
9/8-7*65+4321 = 3867.125
9*8-7/65+4321 = 4392.892308
9/8*7-654+321 = -325.125
9*8/7-654+321 = -322.7142857
9/8-7*654+321 = -4255.875
9*8-7/654+321 = 392.9892966
9/8*7-6543+21 = -6514.125
9*8/7-6543+21 = -6511.714286
9/8-7*6543+21 = -45778.875
9*8-7/6543+21 = 92.99893015
9/8*7-65432+1 = -65423.125
9*8/7-65432+1 = -65420.71429
9/8-7*65432+1 = -458021.875
9*8-7/65432+1 = 72.99989302
9/8*76-5+4321 = 4401.5
9*8/76-5+4321 = 4316.947368
9/8-76*5+4321 = 3942.125
9*8-76/5+4321 = 4377.8
9/8*76-54+321 = 352.5
9*8/76-54+321 = 267.9473684
9/8-76*54+321 = -3781.875
9*8-76/54+321 = 391.5925926
9/8*76-543+21 = -436.5
9*8/76-543+21 = -521.0