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: Dan has $ 4. He bought a chocolate for $ 7 and a candy bar for $ 2. 

 Question: How much money did he spend to buy chocolate than he did to buy candy bar?

Solution: 5