There are 29 different books and 40 different movies in the ' crazy silly school ' series. If you read 15 of the movies and watched 31 of the books How many more books than movies have you read?
There are 29 different books and 40 different movies in the 'crazy silly school' series. 

If you read 15 of the movies and watched 31 of the books, then you have read 15 + 31 = 46 books/movies in total. 

However, of those 46, only 29 are books. This means that you have read 29 - 15 = 14 more books than movies.