The major writing utensil in American schools is the No. 2 pencil. Sometimes its portrayed as a big yellow wooden one with a juicy pink eraser, and nowadays I see more mechanical pencils.
Students in Taiwan rarely use pencils. They use pens all the time and therefore need white-out as an eraser.
One theory of mine is that Chinese characters are closer together. Writing one Chinese character takes up the space of two English letters. Looking at a paragraph of Chinese characters looks like a solid block of ink while looking at English paragraphs, you can often see each line. Students here have to be much more precise when they write. Therefore, they use pens.
And they are different from the pens that I used in America. The pens can be ballpoint but super thin. You can’t really see the ball on the tip of the pen like you can with pens in America. The pens make scratchy sounds when you write really fast, like the quill in Harry Potter and the Chamber of Secrets.