Have you been taught the pigeon hole principle? Build in the restrictions and then re-arrange around them.

X X X X

In the first position there are 5 possibilities. In the last position there are 4 possibilities. Note that the number 0 is neither even nor odd.

Assumming repetition is allowed, there are 10 possibilities for the two positions in between.

Therefore: (5)(10)(10)(4) = 2000.