how about a classroom
Why didn't we put ( there) between (are) and (in) ?
You can say : how many boys are there.
You replace "there" by "in the class"
Kids / children > /أولاد
Kid/ child > ولد
Boy صبي/ فتى
Boys صبيان /فتيان/فِتيَة
( and it's important to write فِتيَة like that if you want to use it , because if you didn't , it could be understood like فَتِيَّة because فَتِيَّة means young )