A book has 37 chapters. The second chapter is 4 pages long. If there are a total of 33 pages in the book How many pages are in the first chapter?
There are 37 chapters in the book. 
The second chapter is 4 pages long. 
That means there are 33 pages left in the book. 

We can set up an equation to solve this: 

x + 4 = 33

x = 29

That means there are 29 pages in the first chapter.