He was calculating in his head.

It is important to understand the importance of health.

This math problem can be solved using a specific formula.

We have our wedding ceremony tomorrow.

In French, the partitive article plays a very important role.

The greater part of the time is spent on work.

This project was partially successful.

He is a world-famous mathematician.

Combinatorics is a branch of mathematics that studies combinations of things.

Combinatorics is a branch of mathematics dealing with issues of order and choice.