There are many different books in the ' crazy silly school ' series. If you have read 37 of the books and are yet to read 3 books How many books are there in the ' crazy silly school ' series?
There are many different books in the 'crazy silly school' series. 
If you have read 37 of the books 
and are yet to read 3 books 

How many books are there in the 'crazy silly school' series?

There are a total of 40 books in the 'crazy silly school' series.