The so-called estimation refers to the rough guess used when accurate calculation and judgment are impossible or unnecessary in calculation and measurement. As far as its function is concerned, the number of times a person estimates in his daily life is far more than the number of times he calculates accurately. It can be seen that estimation plays an increasingly important role in modern society. Therefore, the cultivation of primary school students' estimation ability has become one of the hot spots in the current primary school mathematics education reform, and "strengthening estimation, diluting written calculation and introducing computer calculation" has become a new educational concept. The new Curriculum Standard clearly requires the development of students' sense of numbers, and also emphasizes the requirement of estimation. That is, "the result of the operation can be estimated and the rationality of the result can be explained". Then, in primary school mathematics teaching, how to improve the effectiveness of students' estimation process while developing students' sense of numbers, let the estimation process reflect strategies, and let students feel the thoughts and methods in the process, so as to really improve their estimation ability? Combined with my own teaching practice, I think we can start from the following aspects. First, change your mind and feel the value of evaluation. To improve primary school students' awareness of estimation, teachers need to change their ideas, feel the important role of estimation in life, pay attention to estimation, and change students' attitude towards estimation based on specific conditions, so that students can correctly understand and experience the practical value of estimation and change "unwilling to estimate" into "fond of estimation".