Prefix notation is a notation where the operator comes before the operands.

This is the first time I've seen this notation.

Prepositions are an important part of grammar.

I placed the materials before the important meeting.

I go to drink coffee in front of the station every day.

I used to live in Tokyo before.

I remember talking to him before.

Postfix notation is one method of expressing calculations.

There is no choice but to move forward.

He was waiting in front of the house.