This paper presents the development of web application for practicing calculation with multiple goals. A set of software packages known as MERN (MongoDB, Express.js, ReactJS, Node.js) was used, mainly based on the JavaScript programming language in combination with other software packages and libraries that come from the family of these technologies. This paper describes the technical implementation of the application that uses these technologies but also the representation that shows the functionalities that the application itself provides. Its main goal is to master mathematical operations in the lower grades of primary school, increase their motivation and desire to learn new teaching content through fun and competitive material. On the other hand, the application also facilitates the whole process for the teacher who uses it to supervise students, provide feedback on the adopted content and guaranteed time savings in creating the content of the school lesson. At the end of the paper, the existing mathematical applications are studied and their advantages and disadvantages are analyzed including techniques for increasing motivation in students. It turned out that the developed application is a combination of all the good features that much larger, analyzed applications have and as such a good core and basis for upgrading and introducing itself in schools.