There are two cases: $Case \hspace{1mm} 1$. All the digits are even. There are $ 4.5.5 = 100$ such numbers. $ Case \hspace{1mm} 2$. Exactly one digit is even. If it is the hundreds digit, then there are $ 4.5.5 = 100$ such numbers. If not, then there are $ 2.5.5.5 = 250$ such numbers. Hence the final answer is $ 100 + 100 + 250 = 450$.

Or in that way: We have 90 ways to choose first to digits. If sum of that two digits is even, then can add one of 5 odd digits. If sum of that two digits is odd, then can add one of 5 even digits. So we have 450 numbers.