Teaching objectives:

Understand and master oral division with divisor as two digits; You can skillfully estimate and calculate the division in which the divisor is a two-digit number. In the process of exploring division operation, students' preliminary reasoning ability and group cooperative learning ability are cultivated.

Key point: Students learn how to divide by two digits.

Difficulties: improve students' mathematics learning ability in the learning process.

Teaching aid preparation: pictures

Teaching process:

Review preparation

(1) oral calculation

80÷20 50÷ 10 ? 60÷30 ? 160÷80

100÷50 250÷50 360÷60 390÷30

(2) Last class, we left a verbal problem: 540÷60=?

Students, how should I calculate this problem orally?

Review can play the role of knowledge transfer, which is beneficial for students to learn new knowledge in the future and let them see the connection between old and new knowledge.

(B) the introduction of new courses

1. Students perform independent calculations.

2. The method of oral calculation should be affirmed as long as it makes sense, but students should also be guided to learn to absorb other people's good methods and choose the one that suits them best.

Such as: 60×9=540? So 540-60 = 9

Or? 540÷6=90 ? So 540-60 = 9

Or 54 divided by 6 and 10 equals 9, then 540÷60=9.

Students already have the basis for finding the quotient and the first red dot with formulas. Let the students calculate and exchange methods by themselves. )

Step 3 ask questions: question pockets

We have just learned oral arithmetic in which divisor is a two-digit number. Can you tell us what the division of spoken English is?

Do you have any questions? Can you give an example to ask questions?

There is a question pocket behind every red dot question. Encourage students to learn new knowledge and then ask questions, ask their own questions, solve problems and improve their ability to learn mathematics. )

(3) Consolidate exercises

1. Oral calculation

840÷60= 480÷30= ? 750÷50=

630÷30= 600÷30= ? 720÷60=

2. Human blood can circulate in human body 1 hour 180 weeks.

(1) How many weeks does blood circulate in the human body every minute?

(2) How many seconds does it take for blood to circulate once a week?

The speed of the plane is 720 kilometers per hour and the speed of the train is 90 kilometers per hour.

(1) How many times is the plane faster than the train?

(2) What other questions can you ask?

(D) class summary

What did you gain from your study? What should I pay attention to when calculating? (When summing up, pay attention to cultivating students to pay attention to calculation and inspection at all times and develop good habits. )

Blackboard design:

540÷60=9

Think about it: 54 tens divided by 6 tens equals 9.

60×9=540 ? So 540-60 = 9

Or? 540÷6=90 ? So 540-60 = 9

Homework design: 1, independent exercises 5 and 6. ?

2. Practice related exercises synchronously.