The yuan is the name of the unit in which renminbi transactions are denominated, but also refers to the currency generally. Thus, a person might pay for a meal using a 20 yuan banknote, and get some yuan and jiao (a tenth of a yuan) in change (the jiao is further divided into 10 fen). But it is all renminbi. This is similar to the pound sterling, which is the name of the British currency, while the price of a pint of beer in a London pub would be stated just in pounds.