InfoPath Dev

Hi, I am working on inventory request form. i have inventory list and inventory request form library. on infopath i have placed repeating table to show inventory data, user can select item from inventory. now i want to calculate the price. user select 4 qty and its unit price is 20. how do i calculate item price and same how do i calculate grand total. item unit price qty total 1 10 5 50 2 20 2 40 grant total 90 pls guide thanks

You can do this in a calculated value - if the value is in the repeating table or section, you can just use a formula that is qty * price. If you use a field in the form for this, it will make it easier to create your grand total - use a sum formula. If you need a hand, attach your form under the options tab in a reply.