There has been a global consensus to develop computational thinking (CT) in primary education, but one of the biggest questions regarding the development of CT is how to properly evaluate the level of CT of pupils. Bebras tasks are believed to develop CT and are a popular tool to measure the level of CT in many studies. The Bebras tasks are usually the first contact with computer science and computer science topics like algorithms, programming, or modeling for many pupils, making them a promising tool for this task. However, the relationship between Bebras tasks and CT is relatively new, and the expected development of CT through Bebras tasks has not been sufficiently evaluated, especially in primary schools, due to the lack of valid instruments for assessing CT. The aim of this research was to design a learning material for developing CT using Bebras tasks in the form of a textbook. Bebras tasks were selected according to the CT skills they were related to and then categorized into chapters of the textbook. We then employed pre-test and post-test experimental research and taught one group with regular learning materials and the second group using our Bebras textbook. We used Zapata-Cáceres‘ competent Computational Thinking test to measure the level of CT before and after the lessons to find out if our textbook can develop CT of primary school pupils and whether Bebras tasks might be thought suitable for the development of CT. The results indicate significant improvements in a number of CT skills using our Bebras textbook, as well as intriguing gender differences.

Keywords: Computational Thinking, Bebras Tasks, Computational Thinking Evaluation, Computational Thinking Development.