He was bedridden with illness for several days.

I can't solve this problem because there are too many numbers.

It is important to understand the importance of health.

His explanation was impossible to understand.

He is passionate about researching pure mathematics.

He is majoring in applied mathematics at university.

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.