Let the students talk about the calculation method of multiplying decimal and integer and the division of decimal when the divisor is integer.

On the law of decimal size change caused by decimal position movement and the problems that can be solved by applying this law.

Talk about how the decimal size changes after the decimal point moves in the group.

Second, practice and application.

1. orally calculate the following questions.

0.5×5 0.45÷9 100×0.39 0.04× 1000

1.2÷3 20×0.4 0.07÷2 7÷ 100

2. Write the product of two numbers in each column according to the product in the first column.

Factor18180180.181818.

Factor 25 25 250 25 2.5 25 0.25

Product 450

3. Use vertical calculation.

2.5×4.4 39×0. 15 0.57×23

65×3. 12 0.37× 16 14.3×38

4. First talk about which questions have quotients below 1, and then calculate.

(First, let the students judge which questions have quotients less than 1 according to the characteristics of the questions, and then verify whether this judgment is correct through calculation. )

6.48÷ 18 12.6÷35 0.465÷ 15

9 1.2÷24 45÷72 5.55÷37

5、

480m = () km 0.2m2 = () square decimeter.

78g = () kg 3.46t = () kg

150cm = () m 007L = () ml