Fixing or rounding #VALUE! Error

As I have also written in the image:

Because the Cell G2 and E2 contain the symbol “€”, simple calculations show an error.
How do I fix this?
I prefer a solution where I will be able to keep the “€” symbol but if that doesnt work or is too difficult (I am a newbie at this program) I prefer to be able to easily remove ALL “€” symbols within the document. How do I go about doing that?

Your cell content is of type Text instead of Numeric. Work in a locale that actually has the Euro as currency and uses the comma decimal separator to be able to recognize input containing the symbol and , separator, or enter only the numbers according to your locale and format the cells as currency. See also this FAQ.