ELI5: Explain Like I'm 5

Preparatory subject

A preparatory subject is like when you get ready to go outside and play. You have to put on your coat, hat, and gloves to get ready for the cold weather. In the same way, a preparatory subject is a class that helps you get ready for another class that might be harder or has more information.

So just like you put on your warm clothes to protect your body from the cold weather, a preparatory subject helps you protect your education by giving you the skills and knowledge you need to do well in a harder class. It's like a stepping stone that helps you build a strong foundation for your education.