Math
Tom has forty-four books and forty-two magazines in his library. He bought several books at a yard sale over the weekend. He now has ninety-one books in his library.
How many books did he buy at the yard sale ?
How many books did he buy at the yard sale ?
91=total number of books in library
x=number of books he bought
44=number of books he started with
x+44=91
x+44-44=91-44
x=47