This article describes research on the use of a differentiated approach in assessing students' academic achievements during mathematics lessons. The study used theoretical and empirical research methods. In particular, normative documents and scholarly literature were reviewed, and in 2021, the study conducted a survey of online mathematics teachers from Kazakhstan on a differentiated approach to teaching. The study then analyzed the collected data using Spearman's Rank Correlation Test and T-test. Firstly, the research shows that teachers mostly understand differentiation in the lesson as an adaptation of educational material to the needs of students and the use of tasks of different levels of difficulty. Secondly, there is a correlation between the understanding of a differentiated approach and the needs of teachers. Thisresearch results expect that it would give an idea of the readiness of mathematics teachers to apply a differentiated approach in assessment and develop recommendations for its application further.