The contents of this textbook include: decimal multiplication, position, decimal division, possibility, simple equation, polygon area, mathematical wide angle and comprehensive application of mathematics.

In number and algebra, this textbook arranges decimal multiplication, decimal division and simple equations. The multiplication and division of decimals is the basic knowledge and skills that students should master and form. This part is based on the previous study of four integer operations and decimal addition and subtraction operations, and its purpose is to continue to cultivate students' ability of four decimal operations. The unary equation is a unit that focuses on teaching the basic knowledge of algebra in primary school. In this unit, the contents of expressing numbers with letters, the properties of equations, solving simple equations, expressing equivalence relations with equations and solving simple practical problems are arranged, which further develops students' abstract thinking ability and improves their ability to solve problems.

In terms of space and graphics, this textbook arranges two units: position and polygon area. On the basis of existing knowledge and experience, students can gain the experience of inquiry learning through rich mathematical practice activities, so that they can understand the meaning of columns and rows in specific situations and know the rules for determining columns and rows. Can understand the meaning of number pairs initially, and can use number pairs to represent the position of objects in specific situations. ? Combined with specific situations, let students experience the process of abstracting a specific seat map into a plan with rows, improve their thinking ability and develop the concept of space. Let students experience the close relationship between mathematics and life, further enhance their awareness of observing life from a mathematical perspective, master the area formulas of parallelogram, triangle and trapezoid and their relationships, infiltrate the mathematical thinking methods of translation, rotation and transformation, and promote the further development of students' spatial concept.