An open cluster is a cluster of stars that consists of dozens to thousands of stars.

Observing star clusters is a very important task for astronomers.

He read scores of books.

Astronomers have discovered a new globular cluster.

He solved a large number of problems.

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

Understanding numbers is important for solving math problems.

He was bedridden with illness for several days.

There are a thousand meters from my house to school.

He used his alphanumeric skills to create a computer program.