The math master who punished Anne's talking in class with writing assignments was Mr. Keptor.
By her own admission, Anne was quite garrulous in class. Her "old math master", Mr. Keptor, became annoyed by her constant talking, and as a punishment, assigned her to write a three page composition entitled "A Chatterbox". Anne was at first stymied at what she should write, but after much thought, argued creatively and effectively that talking was a feminine characteristic, and that though she "would do (her) best to keep it under control", she should never be cured of the malady, as it clearly was an inherited characteristic. Mr. Keptor laughed amiably at Anne's argument, but when her constant talking continued, assigned her a second essay, this time entitled, "Incurable Chatterbox". Anne completed this assignment as directed, but alas, was still not able to curb her talking. Frustrated, Mr. Keptor assigned her a third composition with the absurd title of "Quack, Quack, Quack, Says Mrs. Natterbeak". Challenged to think of an original response, Anne enlisted the help of a friend who was good at writing poetry, and completed the composition in verse. The result was "perfect"; Mr. Keptor laughed at the joke and read the poem aloud to the class. Anne received no more extra work as punishments, and was from then on allowed to talk in class as she pleased (Sunday, 21 June, 1942).
Through her diary entry about her interactions with Mr. Keptor, Anne reveals herself to be an especially intelligent, creative young girl. She is fun-loving and has an strong sense of humor.