Teaching objectives:
1 Let students experience the initial formation of the concept of "time". Understand the meaning of "several times a number". The concept of "time" was initially established.
Ask students to clarify the mutual transformation between quantity and quantity. Can find out how many times a number is, and can solve simple practical problems.
Cultivate students' problem consciousness, cooperative communication ability, hands-on operation ability and language expression ability.
4. Stimulate students' emotion of learning mathematics, and let them experience the pleasure of successfully solving mathematical problems.
Teaching emphasis: Understand the meaning of "several times a number".
Teaching difficulty: help students to know "how many times is a number, that is, how many times is a number".
teaching process
First, put forward the learning objectives.
1. List the formulas according to the following diagram and explain their meanings.
○○○ ○○○ ○○○ ○○○
□○□=□
△△ △△ △△
□○□=□
★★★★★ ★★★★★
□○□=□
Teacher: You guys are great! Let's play a graphic game today!
2, put forward the learning objectives
First, understand the meaning of "several times a number". The concept of "time" was initially established.
B, can find a number many times, and can solve simple practical problems.
Second, show the learning results.
1, displayed separately in the group.
Students teach themselves, complete examples and communicate in groups.
Step 2 show it to the class
(1) Example 2 Students set up sticks and squares with sticks.
How many diamonds did you put in? How many sticks were used? How many/much? Four?
Put two squares and use some sticks. How many? How about three or four?
Teacher: Three or four can be said to be three times as many as four. (Let the students say it several times)
How much is three times four?
Can you enlarge it to four times? But not square. Tell me how many times you played it.
Teacher: Pointing to two and four, ask: What can I say? Who can swing twice as much as 4?
Teacher: Say the following several times or several times.
Three twos, two fives, four sixes and three fives.
3 times of 2, 0 times of 65438+5, 6 times of 4 and 4 times of 3.
(2) Example 3
A linear pendulum: ●●
Pendulum in the second row: 4 times that in the first row.
How should I put it? Who has this idea? Student demonstration.
Report: How many circles are put in the second line? Why? How can I make it clear?
What is the multiple of a number? How to use mathematical formula to calculate? Why?
(3) Example 4
Students ask math questions according to the information in the picture.
Teacher: What do you mean by cleaning tables and chairs twice as much as sweeping the floor? Students talk about the significance of drawing lines and how to solve them.
Third, expand the extension of knowledge.
1, make a textbook. Put it yourself first, and then how to put it on the second line. How to calculate?
Grandpa bought two eggs yesterday, and today he bought three times as many eggs as yesterday. Would you please calculate how many eggs he bought today? Students calculate and talk about their ideas.
3. Practice. Students should read the meaning of the question clearly before calculating.