Populate values from Opportunity to Account

Hello, I need to implement the following functionality.

When an opportunity is closed as WON, populate few values (Currencies) from opportunity to its Potential Customer (Account).

Then in the account, the values would be added.

If there are more than 1 opportunity linked to the same Account, values should keep on adding when all opportunities are closed as won.

Example: Customer = ABC Opportunity 1 closed. Field A in Account = 500$

               Customer = ABC Opportunity 2 closed. Field A in Account = 1000$

               Customer = ABC Opportunity 3 closed. Field A in Account = 1500$

Any help would be appreciated.

Thank you.