The buy or sell action you take to enter a trade always applies to the base currency. The opposite action automatically applies to the quote currency. So, if you buy the EUR/USD, this means you’re buying euros and selling US dollars. If you sell the EUR/USD, you’re selling euros and buying US dollars. The base currency is always worth one. The quoted price shows how much of the quote currency you’ll get for one unit of the base currency. So, in this case, 1 EUR is worth approximately 1.33 USD.