Implement Mathematic Formulas like (+,-,*) on Running time inside the GridView Footer Template

Hi Developers,

i want to Calculate value between one or more than one GridView Footer Template Textbox .
and also display the Sum in a Label on Running Time.

In my Project i need to Implement Mathematic Formulas like (Addition , Subtraction & Multiplication) on Running time.I have done this task.as Manual TextBox and Labels.

But this time i want that the Same Mathematic Formulas like (Addition , Subtraction & Multiplication) on Running time Within GridView Footer Template
Make Calculation Between two or more than two text boxes and display it a label on Running time.
Also i need to done this task GridView Edit( Edit item Template).
I am want this only on Client Side.Server side i have already done.

i am trying with via google.

if anyone know how to done my requirement please suggest me to i am done this task.

thanks with
Paul.S
Prayer through , Impossible becomes HimPossible