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.
Example: Context: Sam is 6 feet tall and Alex is 5 feet tall 

 Question: By how many feet is Sam taller than Alex? 
Example solution: 1
Example explanation:  Sam's height - Alex's height = 6-5 = 1

Problem: Context: For Gwen's birthday she received 5 dollars from her dad. Her mom gave her 7 more dollars. If she spent 4 dollars. 

 Question: How much more money did she receive from her mom than she did from her dad?

Solution: 2