Testing values in logic

I have used logic to post values to accounts based on the account number. Now I need to post values based on account values. Logically what I want to do is this;

if account-1 value = account-2 value post account-1 value to account-3

If Excel this would be a simple formula. In script logic I am struggling to find examples that reference the account values rather than the account ids.

Thanks

Cliff