Calculate Fields, just want to collect positive areas

Calculate Fields widget I'm using

"mart toplam ekders" in the collection I did it just want to collect positive areas

For what I understand, you are not having difficulties withe the calculations, you just don't want to receive a submission with a negative results?

If my assumption is correct, you can simply create a condition to show the submit button only if there are positive areas, like this:

Please try my example here: http://form.jotformpro.com/form/50646548344965?

Let us know if you need anything else, we will be glad to assist you.