In this thesis we analyzed the competitive tasks for middle school in Informatics for the past five years and their solutions. We also compare the necessary knowledge from the official propositions with the material of the approved textbooks (SysPrint and Školska knjiga) according to the Catalogue of compulsory textbooks for school year 2018/2019 and with the outcomes of the domain Computational Thinking and Programming (Curriculum of Middle and Secondary School Informatics in the Republic of Croatia). Through the first chapter we described in detail the competition in Informatics in the Republic of Croatia. We explained how organized and what are the categories and levels of competition. Particular attention was given to the category Algorithms for Middle School: Application of Algorithms and LOGO, whose tasks have been analyzed in detail in the following chapters. In the second chapter we studied the tasks from the competition for the fifth grade of middle school in the Applications of Algorithms and LOGO categories. We looked at the students competences needed for competitive tasks and compared them with the contents of the studied textbooks and the Curriculum of Elementary and Secondary School Informatics in the Republic of Croatia. For each task, we pointed out why we chose an individual task and what knowledge is needed for the student to solve the task. The third chapter was an analysis of competing tasks for the sixth grade of middle school in the Applications of Algorithms and LOGO categories. At the beginning of the chapter, we briefly compared student's knowledge of the official propositions with the topics discussed in the textbooks and the outcomes of the Computational Thinking and Programming domain. Also, as in the previous chapter, we commented on featured competitive tasks and solutions to these tasks. In the fourth chapter, we studied competing tasks for seventh grade students in the Algorithms for Middle School category. At the beginning of the chapter, we compared the necessary knowledge for compulsory competitions with the elementary course of Informatics. Then we chose the sample assignments from the competition and described them in detail. The fifth chapter was an analysis of competitions for students of the eighth grade in the Algorithms for Middle School category. As in the previous chapters, we first compared the compilation of competitive assignments with regular teaching, and then we conducted a detailed analysis of the tasks appearing in the eighth-grade student competition.