The number of 3-digits number (including the numbers that start with 0) is

But we have to eliminate the numbers that star with 0, wich means

So, we have 3-digits numbers.

To count the even numbers we put an even digit on the unit place. There are 4 possibilities: 0, 2, 4, 6.

If the unit digit is 0, there are even numbers.

If the unit digit is 2, 4 or 6, there are even numbers.

So, there are even numbers.