Acrobat calculation help!! (FORMS)

Okay I have a PDF of a my cataloge that I want to add some forms to since it will be web use, i want to add QTY boxes so they can save the PDF and email me their order.

The product only comes in boxes of 36. So i want a box that automatically calculates sum of qty boxes when entered.

ie. product 1 QTY = 6
product 2 QTY = 12
Product 2 QTY = 18

TOTAL QTY = 36

Ive tried everything I could.

made 4 form boxes Box 1-3 i named QTY and box 4 I named total

in the total box properties i selected sum(+) and added the 3 qty boxes.

Also chose simple calculation mode and typed =QTY1+QTY2+QTY3 also

Boxes show up on the PDF after I save it but the total does not change from 0 at all. Please help.

thanks.

 

Okay I dont know what was going on but i started from scratch and it worked.

when I click on the hand tool it works, but when I open it in preview it wont calculate the total!

is preview crap?

thanks