Thanks for the reply!
Unfortunately, I am fairly new to development, not quite understand what they write. I can not decide which one would be good for me. Here, the customer must be exactly the quantity you want to enter. (Eg. 2.1 kg of meat) And I would like to specify how much of the system is 10 ounces of a given product. From this data, the system is to be calculated on the total amount that is listed on the bill as well. Can you give me detailed instructions to write? Thanks!