摘要：We present a study in which we consider whether the learners, who had mathematics instruction in the 9th grade of primary school in heterogeneous groups, significantly differed in their mathematics achievements measured by using the external and internal assessment of knowledge from the learners in homogeneous groups. No statistically significant differences in the average achievements were found in the external assessment. On the contrary, in the internal assessment of knowledge the learners in homogenous groups on average had significantly higher achievements in comparison to the learners in heterogeneous groups. The analysis of covariance performed in homogenous and heterogeneous ability groups showed that the learners, who were placed in the lower or middle third after the initial examination in their school, in the final external examination progressed relatively better in heterogeneous groups. The learners who were placed in the upper third in their school according to their mathematics achievements showed no differences in this regard. The internal assessment of knowledge displayed that the learners who were placed in the middle or upper third in their school after the initial external examination, in the final examination progressed relatively better in homogenous groups. The learners who were placed in the lower third after the initial external examination in their school showed no differences in this regard.
关键词：grouping of pupils; individualization and differentiation; internal assessment of knowledge; external assessment of knowledge; mathematics.
