What is the summary of Matilda Chapter 10?

As the first week of school progresses, Matilda has no trouble making friends, and her first and best friend is a small, spunky girl named Lavender. They very quickly begin to hear stories about their Headmistress, "The Trunchbull" (pg. 102), starting with the fact that she detests the youngest children the most. However, in addition to hearing about the Trunchbull's behavior, they also hear about how students can get back at her by planning tricks and pranks. The students are often punished for their behavior, but it is all a part of the ongoing battle between them and Trunchbull.

Just as the girls finish hearing about how the Trunchbull was an Olympic Hammer Throw champion and that she likes to throw children to keep her arm in shape, they witness just such an event. Annoyed by a young girl's pigtails, the Headmistress picks her up by them and throws her across a field. Matilda and Lavender are told that the parents of the mistreated children are likewise scared of Miss Trunchbull and that's why they do not confront her. Matilda theorizes that it is also because the stories and events are so extreme that the children are not believed by the parents.