Call activity from workflow

Question

Hi,,

 

My requirement is

 

i am having one WPF form with 3 textboxes and i can enter 2 numbers in the first 2 textboxes and the sum should be displayed in the third textbox.For that i have to write one workflow and one activity and i have to call that activity from the workflow and how to pass thease 2 values to take sum.

 

Plzz help me..

plzz write for me in detail because  i am very muc new to this workflow programming.

 

plzz..plzz

 

Priya