Expected and actual mathematics knowledge of students entering a secondary grammar school

summary:The objective of this work is the analysis and evaluation of the pupils' different levels of knowledge of mathematics, but also their specific knowledge of arithmetic and geometry and their logical reasoning. The research study was conducted in the first years of secondary school were there are the most apparent differences in the level of acquired mathematical knowledge of pupils coming from different schools. Grade assessment of pupils which they get at the primary school is not always a clear indicator of their knowledge. Pupils with the same grade often have significantly different levels of knowledge. The article presents selected results of the research such as the identification of levels of knowledge of pupils coming from different primary schools and of their specific weaknesses