Mrs.Smith baked 6 dozen cookies for the party.The guests ate all but 20 cookies. How many cookies were eaten?

Mrs. Smith baked 6 dozen cookies, which equals 72 cookies (since 1 dozen is 12 cookies). If the guests ate all but 20 cookies, that means 20 cookies remained uneaten. Therefore, the number of cookies eaten is 72 - 20 = 52 cookies.