This a classic book with a great story! The Lexile level is 730L. would use this in a 1st grade classroom in mathematics. I would make a Yellow Brick Road of paper for the classroom floor (or go outside and use yellow street chalk). I would ask the students, "How many bricks would it take to make our yellow brick road cross the hall? run across the playground? down the street? What about if the individual bricks were smaller or larger?"
I would also use this in reading with compare and contrast. The Wonderful Wizard of Oz has been called the first American fairy tale. I would have students use a Venn Diagram to compare and contrast with other fairy tales they are familiar with (Grimm, Perrault, etc.).