Mary has a mystery book library. She started with 72 mystery books at the beginning of the year. She joined a book club that sent her 1 book each month of the year. She went to a bookstore halfway through the year and bought 5 more books, then bought 2 books at yard sales later. Her daughter gave her another book for her birthday, and her mother gave her a series of 4 books when Mary visited her. She donated 12 books she didn't want to read again to a charity shop and sold 3 to a used book store. How many books did she have at the end of the year?
Thoughts? Step-by-step reasoning:
Mary got 1 * 12 = 12 books from the book club. She bought 5 + 2 = 7 books. She was given 1 + 4 = 5 books. She got rid of 12 + 3 = 15 books. Thus, at the end of the year she had 72 + 12 + 7 + 5 - 15 = 81 books.
Thus, the answer is 81.