Exams in engineering have mostly applied math in almost all subjects. They required a bit of narrative and finally solutions to real-life problems/case studies. While the text was known to everyone, we feared we could go wrong in calculations and got a wrong answer.

To ensure that all answers were correct, we used to form groups and compared the final numerical answers. If all got the same answer, meant we were all correct...and if one of us got a different answer, he would do it again.