The measurement standard of 89 pages in the first volume of the second grade mathematics refers to the understanding of length units and time. The first volume of the second grade mathematics textbook arranges the length unit and cognitive time in quantity and measurement. This part of the content is closely related to life. Through the quantitative development of quantitative thinking in life, children can find mathematics everywhere in their lives. The length unit is a method to learn some knowledge of length measurement, understand the actual length of 1cm and 1m and the advancing rate between them, and get a preliminary understanding of line segments, learning amount and drawing line segments. Knowing time means knowing the actual meaning of time unit hours, minutes and minutes, knowing 1 hour =60 minutes, feeling the close connection between time and life, and forming a good habit of observing and cherishing time.