Several Textboxes values into one textbox

Dear Friends

How to solve this, i want result in texbox1, values from Textbox2 to Textbox7.

Textbox1.value = (textbox2.value + textbox3.value + textbox4.value +textbox5.value +textbox6.value +textbox7.value )

Your Help will be Greatly appreciated.

Thanks in advance
Sagar007