2. Ups and Downs of Shopping Roberto is shopping in a large department store with many floors. He enters the store on the middle
floor from a skyway, and he immediately goes up three floors to the
housewares department. Then he goes down five floors to the children's
department. Then he goes up six floors to the home entertainment
department. Finally, he goes down ten floors to the main entrance of the
store, which is on the first floor, and leaves to go to another store down
the street. How many floors does the department store have?