Assessment skill in teaching in general, and in teaching Maths in particular, is an essential skill for teachers. Developing assessment skills help teachers assess students more effectively and accurately, to adjust their own teaching activities and the students’ learning activities in a timely manner. Understanding the role of assessment in teaching and learning, especially in teaching Maths at primary schools, we are interested in developing assessment skills for Maths teachers at primary school. For example, skills in planning assessment, selecting assessment methods and tools, and regularly assessing students’ learning activities.