We can choose which two of the digits (2nd, 3rd, or 4th) to put zeros
in C(3,2) = 3 ways

The reason this uses combinations and not permutations is because, say, picking
2nd and 4th places to put the two 0's is the same as picking 4th and 2nd, so 
ORDER DOES NOT MATTER.

We can chose the remaining two digits in P(5,2) = 20 ways

The reason this is permutations and not combinations is because, say, putting 3
in the left most unfilled digit and 5 in the rightmost unfilled digit is NOT the
same as the vice-versa.  So ORDER MATTERS.    

Answer C(3,2)*P(5,2) = 3x20 = 60 ways.

Edwin