This article is a part of Artificial Neural Networks Serial, which you can check out here. In the previous blog posts, we covered some very interesting topics regarding Artificial Neural Networks (ANN). The basic structure of Artificial Neural Networks was presented, as well as some of the most commonly used activation functions. Nevertheless, we still haven't mentioned the most important aspect of the Artificial Neural Networks – learning. The biggest power of these systems is that they can be familiarized with some kind of problem in the process of training and are later able to solve problems of the same class – just like humans do!