How do I get totals for all of my form calculations?

I added all the options to a box at the bottom of the form and want to add up all responses (food orders with prices)  But when I fill in form, nothing shows up in that box.  TOTAL DUE $

You have only included one student of four to your form calculation. You need to add all four students to get the total.

I have done it here for you to view/clone:

https://form.jotformpro.com/72125442958965

I modified it a little bit. I seperated your form into four sub totals, one for each student. And then I added up all the sub totals at the end.

Also you need to specify in your paypal setting to accept "User Defined Amount" and select your final total for ""Get Price From".