1. Explore and master the oral calculation method of multiplying integer ten, integer hundred and integer thousand by one digit, experience the diversity of algorithms and perform oral calculation correctly.

2. Cultivate students' awareness and ability to ask and solve problems in the process of discussing and solving practical problems.

Teaching emphasis: be able to calculate a number multiplied by an integer.

Teaching difficulty: mastering calculation method

Teacher-student interaction

(A) create a situation, ask questions

1. Teachers use multimedia to display teaching situation maps and guide students to observe. Teacher: Students, do you know the benefits of afforestation to human beings? Our school plants trees every year. Today, let's take a look at the math knowledge of the young trees waiting for us to plant.

2. Show the theme map

Look at the pictures and tell your roommate what you see. (A * * *, how many bundles of small trees are there? How many trees are there in each bundle? ) Ask the students how many trees are there in "Little Tree One * * *"?

(B) explore oral calculation methods

1, students list and answer the formulas independently, and communicate in groups.

Students list the formula of 20×3 and try to calculate it. Ask the students to talk about the meaning of the formula listed by themselves in the group, and then talk about the calculation method according to the situation of "how many trees are there in a small tree".