Automatically do mathematical calculations and update the column in the table in sql server

Hi

I have disigned the table in the sql server with the two columns

Amount      Percent     Total

I need to set the following calcuation be default in the column "Total" (i.e) 

total= (amount *(Percent/100)).

whenever i add the value in the amount and percent column in the table the column total should be changed accordingly.

Hope this is clear.

If not means please let me know.

thanks