My father is forty years old.

He is in his unlucky year, so he needs to be particularly careful.

This year is my unlucky year, so I need to be especially careful.

I bought three apples at the supermarket.

There are four apples in my bag.

The four of us went to see a movie.

My family consists of four people.

I drew a four in mahjong.

He assisted me in doing my work.

He was very helpful in resolving the issue as our mediator.