Sum Of Textbox Values

ASP QUESTION:????

How can I manage to control that the sum of the values of four text boxes must be 1?
They must be decimal numbers ( from 0 to 0.9 ;)), but when i try to add them to a variable it doesn't work!

Please help!!!!!!

Thanks

:D

Hi, what's the variable defined as? I'd define it as a Decimal and convert all Textboxes to decimal with CDec() when adding.