Students will often be asked by their teachers to carry out research into a particular topic. In the course of their research they may have to use a public library to find the information.

It's unlikely that most students will ever need to know or want to learn all the numbers and categories used by librarians, but this is a good way of encouraging them to think about the relationship between different categories.

This system was created by Melvil Dewey, a librarian who lived at the turn of the 19th and 20th centuries. This system is used throughout the world, so that any book in any part of the world on a particular topic is likely to be found in the same category.

Try this unit yourself for a bit of a challenge!