How to calculate my total?

I wanted to create an online order form for our school but I cant seem to get past the calculation field because I need to sum up the products and multiply by number of weeks. I wanted to integrate paypal and pay by check option. I tried different things but I just cant seem to do it right. Please help!:(

When i cloned your form and worked on it,I realised that calculation for Paypal option works fine. Here is the result. 

However, calculation for check option had some problems. If you apply following changes, it will be resolved.

1. Dropdown fields' prices are assumed as one slice price even though user chooses more than one slice or not choose anything. That's why, you need to consider for each slice option and no slice option. If you fill calculation values of  each dropdown field as below , it will work. Please note that; following screenshot was done for Cheese field. You should arrange values according to prices of other fields. 

2. In addition to above changing, Calculation field which is named as Total at your form need to be changed as below. 

Here is the result of mine when i applied above changing. 

Lastly, I suggest you to look at following user guide related passing calculation to a payment field. You may need to rearrange your form. 

https://www.jotform.com/help/275-How-to-pass-a-calculation-to-a-payment-field