In mathematics, a variable forms part of an equation.

It's difficult to solve this mathematical expression.

Part of this movie is based on actual events.

The formation of a mountain requires millions of years.

He formed a new team.

I love mathematics.

He told me the whole story of the incident.

He is dedicated to the study of organogenesis.

She decided to undergo facial reconstructive surgery.

He is majoring in applied mathematics at university.