Sir Cumference is a series of children's educational books about math by Cindy Neuschwander and Wayne Geehan.

The books have been studied for their use in mathematics education. Most of the characters of the book are named after math terms, such as Sir Cumference

​

• Sir Cumference

• Di of Ameter

• Radius

• Vertex

​

Currently, there are 11 books in the series:

• Sir Cumference and the First Round Table (1997)

• Sir Cumference and the Dragon of Pi (1999)

• Sir Cumference and the Great Knight of Angleland (2001)

• Sir Cumference and the Sword in the Cone (2003)

• Sir Cumference and the Isle of Immeter (2006)

• Sir Cumference and All the Kings Tens (2009)

• Sir Cumference and the Viking's Map (2012)

• Sir Cumference and the Off-the-Charts Dessert (2013)

• Sir Cumference and the Roundabout Battle (2015)

• Sir Cumference and the Fracton Faire (2017)

• Sir Cumference Gets Decima's Point (2020)