The second volume of fourth-grade mathematics mainly includes:

1, meaning of decimals, size of comparison decimals, cyclic decimals.

2. Decimal addition, subtraction, multiplication, division and mixed operation.

3, the decimal point movement law, explore the graphics law, put the graphics.

4. Letters represent numbers, equations, the properties of equations, and solving simple equations.

5. Know right triangle, acute triangle, obtuse triangle, isosceles triangle and equilateral triangle.

6. The relationship between the sum of the internal angles of a triangle and the three sides of the triangle.

7. Know trapezoid and parallelogram.

8. Appreciate and design patterns.

9. Look at objects from different directions.