PLEASE HELP ASAP ! Get data from multiple pages onto one page

I have an app where the user selects quantities of items they want. Each item has its own page for visual effectiveness. I would like to take the quantities entered on each page and combine them onto one checkout page. For example, the user clicks through to bananas. It prompts them to enter the quantity of bananas they want - lets say 5. They then click the back button and return to the list of items. They click another item, apples. It sends them to the apples screen and prompts them to enter the quantity they way. The user enters 6. The user then hits a checkout button where it takes them to a checkout screen. Right here, i want the checkout screen to display that they want 5 bananas and 6 apples. But i want it to display the data as numbers and multiply to find their total. PLEASE HELP!! NEED THIS ASAP!!

This would be simpler on a single page, hiding and showing groups for banana/apple etc.

To do it via pages you will need to store the numbers somewhere.

Either on the user thing, or by creating database entries as you go along. Then sum them all up at the end.