speaking of professionalism, I applied for a job and the human resource manager asked me about how much i netted (income) at my previous job (same field and industry), is this normal and professional for them to ask me this?

I just think it seemed very odd because the job i applied for is like an upgrade of my previous job

Most employers ask your salary expectations, so this could be trying to get the same info but in a different way?

I'd make up a amount that falls within their range. Ie. if their rage is 63-68 DOE, I'd say I got 59-65 - let them figure it out.

I'm assume they didn't actually ask what your net income was.. as that is a strange measure. But it's normal to ask what your salary expectations are, and asking your previous gross income is just poor wording.

Either way, the correct answer to give is what they would need to pay you to take the position.

Some employers are blunt and will ask you straight up how much you were being paid at previous job. This way they can gauge what the minimum cost of hiring you will be, plus they can gauge how valuable you were to your previous company.