One: the unit can only be 2 or 4, and the ten thousand digits can only be 1, 2, 3, 4. 4 At 10,000 digits, the unit can only be 2, and the other three digits are arranged, 3x2x65,438+0 = 6. Similarly, when 2 is ten thousand digits,

There are six kinds. When the digits are 1, 2, 3, there are two ways to select a digit, so there are 2x3x2x 1 = 36, ***48.

Two: In odd numbers, there are three ways to select units: 1, 3, 5. When there is 0, it can only be ten digits, so there is 3×5 = 15, and when there is no 0, it is 3×5×4 = 60. * * * There are 75 kinds. Even numbers, 95 kinds can be obtained by the same method, and the ratio is 15.

Three: space insertion method, the first solo is 5x4x3x2x 1= 120, with six spaces, 6x5x4= 120, * * You120 =/kloc-.