Web Forms

Hi

I wonder if someone can help me. I have created a website using Microsoft
Word. I am trying to create a new page for my site 'an online form' for
submission to me. I have pretty much completed the form however I can't seem
to work out how to create a formula [that works] in the form.

i.e. Entry costs £8.00 whoever is completing the form is going to key inthe
quantity they want. I can't get the form to calculate Qty x Entry and
update. The answer always stays at Nil.

Can anyone help?

Thanks

Suzy