Please teach me how to find the greatest common divisor.

Abstract algebra is a branch of mathematics that studies algebraic structures.

The Paleolithic is the first era of human history.

My grandfather was born in the 1900's.

Abstract algebra is a field of mathematics that studies algebraic structures in an abstract way.

I am studying Modern English.

I have been to Cayman Brac.

He won a lot of money in blackjack.

She always wears a sleeveless shirt on hot summer days.

The dromedary camel lives in desert areas.