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.
One example: Context: Sam is 6 feet tall and Alex is 5 feet tall 

 Question: By how many feet is Sam taller than Alex? 
Solution is here: 1
Explanation:  Sam's height - Alex's height = 6-5 = 1

Now, solve this: Context: A farmer had 175 tomatoes and 77 potatoes in his garden. If he picked 172 potatoes 

 Question: How many tomatoes and potatoes does he have left?
Solution:
80