Teaching objectives
1. Cultivate students' concept of time by deepening their understanding of time units.
2. Some simple time calculations will be made.
3. Develop the awareness and habit of observing and cherishing time.
Emphasize teaching
Simple conversion of difficult time units and the method of calculating elapsed time.
Clock model for preparing teaching materials
Teaching process:
I. Introduction to the guessing game:
1, riddle: short people take one step, tall people take a circle. Short people walk around, tall people walk for half a day.
2. After the students guess the answer, the teacher takes out a clock face model and asks:
(1) "What is a dwarf"? "What do you mean by high?"
(2) "How long does it take for the minute hand to walk a square?" ? How long does it take for the minute hand to walk around? How long does it take to walk a big grid clockwise? How long does it take to walk clockwise?
③ How many points is "1"? 1 How many seconds is it?
3. The teacher demonstrates and sets aside different time for students to read the time. Such as: 5 o'clock, 3: 20, 6 o'clock, 9: 50, etc.
4. Leading the topic: We have learned to look at the time, but how to calculate the elapsed time? In this lesson, we will learn "Calculation of Time" together. (blackboard writing topic)
Second, the new curriculum teaching:
1, teaching Example1:2 hours = () points.
(1) Teacher: 1 equals ...? (Student answers) What about 2 o'clock?
(2) Students cooperate and explore independently.
(3) Feedback
1. 60+60= 120 points
B and 2 are two 60 points, that is, 60×2= 120 points.
(4) Teacher's summary.
2. Complete "Done" on page 4.
Complete it independently first, and then modify it collectively. When reviewing, you can name the students and say what the numbers are. How did you come up with it? Then the teacher summed up conversion of time's method.
Method (1): Hours, minutes and seconds are units from big to small, such as hundreds, tens and hundreds;
Method (2): convert from small units to adjacent large units in hours, minutes and seconds, that is, convert into minutes in seconds. Minute conversion is full 60 decimal 1, and the principle of carry is similar to carry from unit to ten and from decimal to one hundred.
60 seconds =1(101=10)
60 points =1(1010 =1100)
The reverse is also true.
3, teaching example 2:
(1) The teacher projected the scene picture of Example 2 and asked the students to observe the picture carefully and explain its meaning: Xiaoming left home at 7: 30 and arrived at school at 7: 45.
(2) Teacher: How long did it take Xiao Ming to get from home to school?
(3) Students discuss and answer, and try to let students summarize various methods of calculating time:
A, the minute hand turns from 6 to 9. Walk three squares, and it's 15 minutes.
B, 45-30 = 15, which means 15 minutes.
Please tell one or two students when they left home and arrived at school. Let everyone help with the calculation.
Third, consolidate the exercises:
1. Complete "Done" on page 5.
When correcting collectively, you can call the roll in front of the blackboard and do the actual operation.
2. Fill in the blanks:
The score of (1)50 is less than 1 (), and the score of 1 is more than 45 ().
(2) a class is () points, a class is () points, plus () points, is 1 hour.
3. Competition:
How many minutes have passed since the teacher verbally reported the time, such as 3: 00 to 3: 45? The students scrambled to answer, and the teacher rewarded them to see who scrambled quickly.
Fourth, the class summary:
What time is it now? We just started our class at 9 o'clock. How many minutes have passed since we started our class? A class of 40 minutes passed quickly. "An inch of time is an inch of gold, and a thousand dollars can't buy an inch of time." Yes, time is as precious as gold. We should cherish every minute, learn more skills and build our motherland better when we grow up.
Blackboard design:
Time conversion and calculation
2: 00 =( 120) for modification.
Consolidation exercises in hours, minutes and seconds.
Teaching objectives
1, through the material close to the actual life of students, fully understand the practical significance of hours, minutes and seconds in colorful practical activities.
2. Through practice, students master some simple time calculation.
3. Further understand the application of mathematics in real life, enhance the interest and confidence in learning mathematics, and form the habit of independent thinking.
Difficulties and key points:
Simple conversion of time unit and method of calculating elapsed time.
Difficulties:
Solve practical problems in life with the knowledge of the hour hand.
Teaching process:
First, basic exercises
1, complete the third question of "Exercise 1".
Students are required to estimate before the actual verification, and the verified data can be completed by students and parents.
2. Complete question 4 of exercise 1.
Let the students finish independently first, then let them say how each question is compared, and allow them to compare in different ways, as long as it makes sense.
3. Complete question 5 of exercise 1.
Read three examples in the book and ask students to tell how long it takes to do these things according to their own life experience.
4. Complete question 6 of exercise 1.
Let the students try to do it first, and measure the changes of heartbeat and breathing times within 1 minute after running or skipping rope respectively.
5. Complete question 8 of exercise 1.
Students count the elapsed time. If some students have difficulties, let them demonstrate and understand with the help of the clock model, and the teacher will give them appropriate help.
6. Complete question 9 of exercise 1.
Name the topic. Students make independent statements and talk about their own calculation methods.
Second, add a topic.
1, fill in:
1 = () seconds 4: 00 = () minutes 9: 09 seconds 36: 02.
5 minutes = () seconds 150 seconds 02 minutes 400 minutes 04 hours 10 minutes 1 hour.
2. Today's cartoon Happy and Big Big Wolf starts at 2: 05 and ends at 2: 50. How long did the film last?
Third, the class summary
Can I calculate the elapsed time now? What should I pay attention to when calculating the elapsed time?
Fourth, homework
Question 1 in exercise1,1 1.