You are given a math word problem and you are supposed to only use subtraction on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

Let me give you an example: Context: Sam is 6 feet tall and Alex is 5 feet tall 

 Question: By how many feet is Sam taller than Alex? 
The answer to this example can be: 1
Here is why:  Sam's height - Alex's height = 6-5 = 1

OK. solve this:
Context: Rachel had to complete 7 pages of math homework. If she had to complete 4 more pages of math homework than reading homework 

 Question: How many pages of reading homework did she have to complete?
Answer:
3