"It is a boy."
Translation:È un ragazzo.
'Uno' - is used to count (e.g. uno, due, tre, quattro, cinque, sei, etc.) - is used as an article before words that start with s-, z-, gn-, gl-, sc-, sh-, ch-, ps-, pn-, x-, mn-, y-, and some words that start with i-. It can be replaced with 'lo'
'Un' - is used as an article and can be replaced with 'il'. The female form is 'una'. - is used to indicate the number of something (e.g. un libro = one book).
il=the, possibly. Un, does not. Un=a. Hence, E un ragazzo=It is a boy. E il ragazzo=He is the boy. Pardon the lack of accent marks. E without accent marks technically means and, but I suspect tou get the gist. (Essence, point, meaning) (not trying to sound condescending, just aware this is a language learning software, and trying to be easy to understand. Thanks.) :)