If the gross is calculated by adding VAT to an actual base price, than the gross can never be 5.00. A base price of 4.54 will result in a gross of 4.99 and a base price 4.55 in a gross of 5.01.
Your formula doesn't work since there is no base price that can produce a gross of 5.00.
Generally the VAT you do pay to suppliers is deductable from the VAT you get. Problems are cross country because getting that back requires paperwork. And time.
Which is why it is standard in B2B transactions to NOT pay the VAT on the country of origin - which is called "reverse charge". They get your VAT ID, they check it against the EU database and ...