The teaching goal of invariable business law teaching design;
1. Understand the law of constant quotient.
2. Cultivate students' abilities of observation, comparison and abstract generalization.
3. Through experience? Change? With what? The same? Mathematical phenomena guide students to feel dialectical materialism.
Teaching emphases and difficulties:
Understand the invariant law of quotient.
The process of deriving the invariant law of quotient.
Teaching process:
First of all, an exciting introduction.
Interactive guessing 1247 1 1 (one by one)
Teacher: I finally guessed right. Why can't I guess straight ahead?
Health: Finally found the pattern.
Teacher: Today, let's discuss another lesson about law.
Design intention: The introduction of guessing numbers can quickly focus students' attention, stimulate students' interest in learning, and pave the way for exploring new knowledge in this class.
Second, explore the law.
Displays a set of formulas =2.
6? 3=
12? 6=
36? 18=
24? 12=
20? 10=
200? 100
24? 6=
Students' oral arithmetic
Teacher: Look at these formulas. What did you find?
Health: The quotient remains the same, but the dividend and divisor have changed.
The teacher wrote on the blackboard according to the students' answers: dividend and divisor have changed, but the quotient has not changed.
Teacher: How to change the dividend and divisor to keep the quotient unchanged? In this lesson, let's study this problem carefully. What do we study?
Student: Division formula.
Teacher: It is more appropriate, convenient and credible to study several formulas.
Teachers and students discuss together, and finally come to a conclusion: take a set of formulas to study, and then find some formulas to see if they conform to the laws we are looking for.
Show me 6? 3=2 12? 6=236? 18=2
Looking for the law of life
Present student resources and communicate.
Teacher: Can you find the third group? It is pointed out that we can compare from top to bottom and think from bottom to top. Who else can you use as a standard?
Teacher: How many comparisons have you made? What are the rules of several comparisons?
Student: Divider and divisor are multiplied by the same number at the same time, and the quotient remains the same.
Health: If you divide by the same number at the same time, the quotient will not change.
Replay courseware
Teacher: Let's talk about how the dividend and divisor change, but the quotient remains the same.
Student: The divisor and divisor are multiplied or divided by the same number at the same time, and the quotient remains unchanged.
We only studied these three formulas just now. Is the law found credible?
Just multiplied by 2, 3 and 6 is the same. Multiply it by 7, 8 and 9?
Just now, the quotient was 2. Is it 3 and 4?
Teacher: Then each of us will list three more formulas to verify it.
Example verification.
Current resource exchange
Teacher: So, does everyone recognize this rule now?
Design intention: On the basis of students' initial discovery of the law, teachers organize students to pass.
Examples are given to verify whether this phenomenon exists in other division formulas.
For example, this kind of treatment fully shows that students are the masters of the classroom and reflect the students' self.
Subjective learning is conducive to cultivating students' learning quality that dares to question and explore.
The students read aloud in unison.
Teacher: Did you encounter any problems in your research just now?
Show me the formula: 6? 2=3
9? 3=3
2 1? 7=3
Some students have this problem in the process of research (multiples are decimals).
What about dividend and divisor multiplied by 0?
6? 2=3
0? 0=?
Health: It doesn't make sense.
Teacher: Can the dividend and divisor be divisible by 0?
Health: It doesn't make sense.
Teacher: So how can we improve this rule?
Health: divisor and divisor are multiplied or divided by the same number at the same time (except 0), and the quotient remains unchanged.
Design intention: In the process of verification and communication, students naturally discover? Except 0? To really understand the problem? Constant quotient law? .
Third, deepen understanding.
Teacher: Is there a constant law of business in life?
1. Students tell their findings first.
2. Courseware shows that the car travels 2 hours100km, 3 hours150km, and 200km in 4 hours.
what has changed? What hasn't changed?
Health: Time has changed, distance has changed, and speed has not changed.
The courseware shows the typist's typing.
Tell me what has changed. What hasn't changed?
The courseware shows the situation of buying similar goods.
Tell me what has changed. What hasn't changed?
Design intention: extend classroom teaching to extracurricular activities, so that students can have a deeper and broader understanding of the knowledge of this class, cultivate students' feelings of paying attention to life, let students realize the wide application of mathematics in life, let students feel that class is over and their interest is still there, and truly realize that classroom has become a bridge between life and mathematics.
Four. abstract
In this lesson, we learned the law of constant quotient together (blackboard title: law of constant quotient) and talked about our respective gains.
Design intention: Retrospection and reflection are helpful to sort out the knowledge and methods learned, and self-evaluation and mutual evaluation are helpful to enhance students' sense of ownership and form a positive learning atmosphere.
Finally, the teacher sent you a sentence from the mathematician Kepler: Mathematics studies the ever-changing relationship.
?