Since "The Magic School Bus" is a series about science and science education, the DDC number for those books would fall under 500s - Science.
Here are some possible DDC numbers for "The Magic School Bus" books, depending on the specific topic:
* 520 - Astronomy: If the book is about space or stars.
* 550 - Earth Sciences: If the book is about geology, the environment, or weather.
* 570 - Life Sciences: If the book is about biology, animals, or plants.
* 590 - Zoology: If the book is about animals.
To find the exact DDC number for a specific "Magic School Bus" book, you'd need to look at the book's spine or search for it in a library catalog.