Adding VAT to each string in Quote and show summary

Adding VAT to each string in Quote and show summary

Hello,
in the quotes, invoices etc
I can add VAT in 2 ways
1) in each string ${Product.Tax}
2) in summary ${Quotes.Tax}

How to show in the summary ${Quotes.Tax}=${Product.Tax}+${Product.Tax}+${Product.Tax}+etc
VAT of the summ of each string with correct calculation?