Master the derivation of cuboid and cube volume formulas, and understand that cuboid and cube volume can be calculated by multiplying the bottom area by the height, and can be calculated by formulas, thus solving some simple practical problems initially.

In the process of formula derivation, students' hands-on operation ability, abstract generalization ability and inductive reasoning ability are cultivated, so that students can correctly use cuboid and cube volume calculation formulas and answer related practical questions.

Mainly let students solve problems according to the formula of irregular object volume = total volume-water volume. Students can not only solve problems according to the above formula, but also according to the fact that the volume of rising water is a cuboid, that is, the volume of coral stone = length × width × height.

It is emphasized that this height is the height of the rising part of the water surface (total height-water height), and by comparing these two methods, students can find that the basic points of these two methods are multiplication and distribution laws, so as to communicate the connection and comparison between the two methods and further understand the calculation method of irregular object volume.

Surface area formulas of some regular figures;

1, prism surface area: S=S side +2*S bottom.

2. Surface area of cylinder ("U bottom" is the circumference of bottom circle, and R is the radius of bottom circle):

S=U bottom * h+2π r 2。

S=2πR*h + 2πR^2。

3. The surface area of the pyramid (n is the number of hypotenuse of the pyramid, that is, the number of sides):

S=n*S side (triangle)? +S bottom.