CPM(CostPerMille, or CostPerThousand cost per thousand people)
The most scientific way to charge for online advertising is to charge according to how many people look at your advertisement. Charging according to the number of visits has become the practice of online advertising. CPM (cost per thousand people) refers to the average amount of advertising cost shared by everyone who hears or sees an advertisement during the advertising process. Traditional media often use this pricing method.
Then according to the CPM in the title is 500, then a person is 50 cents, 200 thousand, and naturally it is 400 thousand.