Darkwood - Gabby Hutchinson Crouch

Magic is forbidden in Myrsina, along with other abominations such as girls doing maths. This is bad news for Gretel Mudd, who doesn’t perform magic but does know a lot of maths. When her inventions prompt the sinister masked Huntsmen to accuse her of witchcraft, Gretel must act fast to help the Witches save the Darkwood and her home village.