He wrote a new paper on string theory.

He is particularly interested in string theory in physics.

He solved complex mathematical problems using his new calculator.

I am working using a spreadsheet software.

His calculating nature sometimes causes problems.

Please check the statement of account.

It's difficult to solve this formula.

Einstein proposed the theory of relativity.

He is an expert in theoretical physics.

He is studying late into the night to learn a new computer language.