Detailed Instructions: Given a math word problem, answer the following question. You might need to apply addition or subtraction mathematical operators on the numbers embedded in the text to answer the question and then only report the final numerical answer.
Problem:finally they had to roam around 169 factories to make sure they are throwing their wastes properly . if their group went to 69 factories and the second went to 52 how many factories remain unchecked ?
Solution:
48