In simple words, Decision Tree Classifier is a Supervised Machine learning algorithm which is used for supervised classification problems. Under the hood in decision tree, each node asks a True or False question about one of the features and moves left or right with respect to the decision. You can learn more about Decision Tree from here. We are going to use a Machine Learning algorithms to find the patterns on the historical data of the students and classify their knowledge level, and for that we are going to write our own simple Decision Tree Classifier from scratch by using Python Programming Language. Though i am going to explain everything along the way, it will not be a basic level explanation.