Ms. Hanna is Bananas

A popular easy chapter book series is called My Weird School by Dan Gutman. One of his titles, Ms. Hannah is Bananas (AR level 3.6), has the setting in a lower elementary grade. The characters have silly things that happen with their teachers who keep fun in the classroom. Other titles are Mr. Macky is Wacky (AR level 3.7) and Mrs. Kormel is Not Normal (AR level 3.8). For a full listing of Gutman's titles, click this sentence for the Amazon link.