He was calculating in his head.

It is important to understand the importance of health.

The calculation of an indefinite integral can be considered as the reverse operation of differentiation.

In order to calculate the integral constant, it is necessary to solve the differential equation.

The greater part of the time is spent on work.

This project was partially successful.

In French, the partitive article plays a very important role.

Sadayoshi is my best friend.

His composition is based on the cantus firmus.

I take the regular bus to school every day.