It means "How much."
Cuantas means How many.
how much
How many sisters do you have?
It means: How many houses do you have? It could also mean: How many houses does he/she have?
"Cuantas son" in Spanish translates to "how many are there?" or "how many of them." It is often used to ask for a specific quantity or number of things in a conversation.
Compre / compren / compra / comprad unas cuantas cosas.
Cuantas toallas?
How many times a year do you go to the hospital
That is Spanish for "How many rooms does it have?"
cuantas oportunidades necesitas
Translation: Cuantas lenguas hablas?
How many classes do you have on Tuesdays? is ¿Cuántas clases tienes los martes? (Note that days of the week aren't capitalized in Spanish.)