A classmate.
It means "You are a classmate".
"Ella es mi compañera de clase" translates to "She is my classmate" in English.
es una clase de matematicas means is a kind of mathematics
The verb is: 'es'. It comes from the infinitive: ser and is conjugated in the present tense.
Una clase de historia
Una república federal.
Unas clases
A la uno hora en martes. At one oclock on tuesday.
It means, "I need a calculator and a ring binder for the mathematics class."
yo tengo una clase de matematicas y ciencias
I need a calculator for math class.
Martin is an artist and takes an art class.