Please remove the core of this apple.

He solved a large number of problems.

I love mathematics.

In the traditional Japanese number system, Muryo-taisu represents a very large number.

He is good at arithmetic.

He absorbs new information like a sponge soaking up water.

The water service in my house has broken down.

He is majoring in applied mathematics at university.

Deuterium is one of the isotopes of hydrogen.

He is good at solving algebra problems.