Firstly, a person will be able to know his performance. Exams encourage the performance of student. For instance if a person score low grade, it encourage him to work hard in order to score high grade. And also it encourages people to work and learn, creates competition, and develops ones personality and confidence.
Secondly, exam is a way to know how well you understood the topics learnt.
Learning is a 2-way traffic. Whatever you learn in class, you need to apply. And examination is one way to determine how well learning has taken place - is through your answers. Additionally, you can see just how much progress a students has made. Means you can judge the progress of many students at once. For example, teachers can see if any subject should be re-taught or explained differently.
Lastly, sometimes with exams, it can create competition, which pushes the competitioners to do their best. Means there are some organizational, governmental or individual making exams in order to find out the best students in order to assist them. For instance, if a person passes the exams and got a good result, it helps to get a scholarship which will bring to have a good job. Additionally, it helps the person to get a discount from registration fee. For example there are some universities if a student score high grade this will enable the student to get at least 50% discount of registration fee.
On other hand, there are a number of disadvantages of having exams; stress is the major one. For some people,