uct is divisible by 13, 17, 19, 23 etc. This means the product (13 x 17 x 19 x 23) has more than two factors. Hence it is a composite number
Frecuentemente ellos "comen" juntos en la cafeteria del centro comercial.
Translation: Frequently they "eat" together in the cafeteria of the mall.
The last one, vas a trabajar because it says tú, vas is the tú form. hope this helps!
