In the engineering department, 70% of the students are men and 180 are women. How many men are there? Let's think first. Chain of thought:
The percentage for women is 100% - 70% = 30%. Since 180 represents 30%, then 180 / 30 = 6 students represent 1%. Hence, 6 x 70 = 420 students are men.
Therefore, the answer is 420.