Learn Portuguese (Portugal): A rapariga tem dezassete anos.

In Portuguese, you don't say that someone "is" a certain age. Instead, you use the verb ter (to have) to express that they "have" a certain number of years. So, A rapariga tem dezassete anos literally translates to "The girl has seventeen years."

Which form of the verb ter is tem?

The word tem is the "he/she/it" form of ter (to have). Because the subject of the sentence is A rapariga (The girl), which counts as a "she", we use this third-person singular form.

I've seen the word "menina" for girl. Why does this sentence use rapariga?

In Portugal, rapariga is the everyday, standard word for a girl or a young woman. The word menina is also used, but it usually refers to little girls. Note: If you ever speak to Brazilians, be aware that rapariga is an insult there, but in Portugal it is completely normal and safe to use!

How is the number dezassete (seventeen) put together?

It is made by combining the words dez (ten) and sete (seven) with an "a" in the middle. Notice that the "s" is doubled to make ss. This is done so the letter keeps its soft "s" sound instead of sounding like a "z".