Assessment is considered one of the most important tools used today by people in almost everything they do and learn. This also applies to school, where assessment is considered as a constant companion to teaching and used in order to develop students' learning and skills. Assessment is also an educational necessity which has different purposes and therefore different consequences.                                                                                                                        

The idea of ​​this thesis was on the basis of the interviewed teacher's perspective to investigate what role the formative assessment has on the development of pupils' learning and knowledge in mathematics for primary education, and explore how the teacher can, according to my informants, work with this assessment practice in the classroom so that it promotes the learning of the students in the best possible way.                                                                

To carry out this study, I used qualitative research studies, the interview method, and also talked to five different teachers in the lower school ages on their view at the work of the formative assessment. Theoretical basis of the thesis is also based on the research that says that the assessment can be used to promote student learning and knowledge, but also the teacher's learning’s in the educational process: assessment can and should be an assessment for learning.                                                                                                                                        The results of my survey show that assessment, in the sense of assessment for learning, is an important part of the work for the school and is used in order to develop both students' learning and skills, and provide support for teachers to develop their own work. The assessment can also be used in many different ways and in many different situations. The study also shows that even the teacher's role in the assessment of student learning and knowledge is extremely important and great. From what all the teachers are saying and based on my own conclusions from the work done, I can see that it is the teacher's task, to constantly be responsible for the development of the pupils' learning and knowledge, and show the way for these students in this process. In addition, play pedagogue planning and the methods he/she uses also an important role for the learning needs of the students. The teacher is seen as the engine for all learning and depending on how he/she use this knowledge and experience her/his students will learn.