How to get the net invoice amount

Hi Friends,

There is the requirement to get the net invoice amount i.e. Invoice amount - Partial payment.

Suppose invoice is of Rs. 1000 and partial payment 450. So it will show only the net invoice value 650.

Because when I am sorting it, it is showing the invoice document and clearing document as well. So if somebody can tell how to get the net balance showing in the invoice.

With regards