The results of the international TIMSS research (2011, 2015, 2019) for Serbia for pupils of the fourth grade of primary school show that their achievement in the field of geometry and measurement is lower than in other areas (such as number). In order to examine the possible causes, we analysed the textbooks for the fourth grade of primary school that were used in schools in Serbia in the year of the research. The aim of the research is to examine two types of knowledge - conceptual and procedural - in mathematics textbooks on the topic of body volume. Based on the research of pupils' achievement in different types of knowledge in measuring length, area, and volume (Tan Şişman, 2010), we formed a list of indicators that indicate opportunities for learning in mathematics textbooks and different types of knowledge about body volume that are presented to the fourth-grade primary school pupils. In the paper, a descriptive method was applied to analyse the content of the textbooks and the interactions among different types of knowledge in mathematical tasks. The main results of the research show that the indicators that are oriented towards the recognition of the conceptual understanding show a significantly lower frequency of occurrence compared to the indicators of procedural knowledge. We see the reason for this in the initial formation of the concept of body volume. The conclusions of the paper point to the concern regarding the interaction among different types of knowledge, and open up questions for further research, especially from the perspective of the research and development of mathematics textbooks in mathematics education.