Textbooks generally have two specifications: one is 15cm wide and 20.5cm high; The other is 2 1cm wide and 30cm high. Buy according to this size.

In terms of paper size, junior high school students are also 32 folio, which is as big as your primary school textbook. High school is now 16, which means it is a little bigger than your composition book.

If you ask how much space it takes up, it's not necessarily because different formats take up different space for the same content.