He is a world-famous mathematician.

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

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

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

Discrete mathematics is an important field that forms the basis of computer science.

The barnacle is a type of marine creature that firmly attaches to rocks and the bottoms of ships.

This old spittoon is what my grandfather used to use.

There are a lot of Asiatic pennywort growing in my garden.

He carefully stores the family's urn.

This copper pot is an ancient craft.