There is a series of books that I read as a kid growing up in the late 70s about two young girls who were witches. In one of the more memorable plots, the girls were having a hard time with their tests in school and they got a pair of magic gloves that, when they wore the gloves while taking a test, they would get perfect scores on the tests. It was a series of books, and I probably got them through the Scholastic Books program, but I cannot recall the author or the title of any of the books.