Excel

Hi,
I need to create form in excel with the below criteria.
Cell A1 should contain drop down list .Data mentioned in the drop down list should be linked to a number.For eg;the dropdown contains item a,b&c. If a is selected then the same cell should display a number.
PS : i'm aware of creating dropdown using data validation.All i need is guidance to link it with a number and make the number appear in the same cell.
thanks in advance.