1. Understanding of the year, month and day. First, the textbook provides pictures of several meaningful days: through the establishment of People's Republic of China (PRC), Beijing's successful bid for the Olympic Games, Arbor Day, Children's Day and other meaningful days, students can get a preliminary understanding of the year, month and day, feel the close connection between mathematics knowledge and real life, stimulate students' enthusiasm for learning, and cultivate students' patriotism and environmental awareness. In teaching, teachers can make these pictures into slides and show them to students one by one. Let the students look at the pictures first and say what scenes are presented and when these scenes happened. Let the students know these meaningful events through raising their hands and the teacher's introduction. Then the teacher asks questions according to each picture, such as: "Do you know that Beijing won the Olympic bid on July 13?" "When is the annual Arbor Day 12?" Wait a minute. Teachers can also ask students to tell what meaningful days they know, discuss them in groups, and then report and communicate. On the one hand, organizing teaching in this way is based on the psychological characteristics of lower grade children, stimulating students' interest in learning and mobilizing their emotional input; On the other hand, it is also to contact students' real life, guide students to learn to observe life from a mathematical perspective, find the year, month and day in life, put mathematics learning in the context of real life, and feel the value of mathematics learning. At the same time, teachers can also educate students on patriotism and environmental awareness in light of specific conditions. (1) For example, 1. This part of the textbook first arranges a more intuitive calendar, and uses the calendar to organize students to carry out a series of activities, so that students can observe the calendar purposefully and answer questions. Let students learn to read the almanac, know how many months there are in a year, which months are 3 1 day (traditionally called big month), which months are 30 days (traditionally called small month), and how many days there are in February, and discuss how many days there are in a year (this is just an almanac used in textbooks, and the algorithm is not emphasized here). On the one hand, the design of teaching materials pays attention to the combination with students' life experience, and strives to let students experience the practical significance of the year, month and day in actual situations; On the other hand, pay attention to the formation process of knowledge and cultivate students' ability to analyze and process information and actively acquire knowledge. At the same time, let students connect abstract time with specific events with their own direct experience and imagination of time. In the "doing", let the students find out their birthdays and their parents' birthdays. Circle them on the calendar with colored pens. The following "doing" requires students to observe this year's calendar and answer questions. Through the experience of the relationship between events and time, let students gradually establish a longer concept of time. In order to help students remember how many days there are in each month, the textbook introduces the fist counting method and records the melody of the big moon. Lively and lively, it helps to improve students' interest in learning. In teaching, teachers can show calendars with slides, so that students can learn to read calendars, and teachers can guide them. If conditions permit, the teacher can ask each student to prepare an annual calendar, or the teacher can prepare some. Here, teachers should let students communicate in groups on the basis of independent exploration. First of all, the teacher asks students to observe purposefully, such as "How many months are there in a year?" "Are there the same number of days in each month?" "Which months are 3 1 day?" "Which months are 30 days?" Wait, let the students observe and think, and then discuss and communicate in groups. For "How many days are there in a year?" Teachers don't have to discuss the calculation method too much. Students can know that there are 365 days in a year through calculation or directly from life experience, so that students can feel the relationship between year, month and day. After students are familiar with the almanac, they can use the almanac to organize students to do some interesting activities. For example, "When is your birthday, and when are your parents' birthdays?" Can you circle it with a colored pen? "Wait a minute. Teachers here can also design other related activities to strengthen students' perceptual knowledge of the year, month and day. Next, the teacher can ask how to quickly remember how many days there are in each month, so that students can think first and then discuss and communicate in groups. On the basis of summing up the students' speeches, the teacher introduced the method of memorizing with fists. Let the students count from January to July with their left hands, and then count from August to December. When counting August, we should pay attention to telling students to start counting from the place where 1 month is counted. Try to let every student learn to count and remember Da Yue's songs. The "doing" below page 48 allows students to do it independently. (2) Example 2. The textbook gives the February calendars of 2004 and 2005 respectively, so that students can find that the days in February are not all the same, and then explain that there are 28 days in February called flat years and 29 days called leap years. Then ask the students to discuss how many days there are in a leap year. Next, the textbook gives the February calendar of 1993 ~ 2004, so that students can find the law through observation: the Gregorian calendar year is a multiple of 4, with 29 days in February and 28 days in other February, so that students can understand the judgment method of normal year and leap year. The textbook introduces the judgment method of flat year and leap year in the following footnote: Usually there is a leap year and three flat years every four years, and the Gregorian year is usually a leap year, but the Gregorian year is an integer and must be a multiple of 400 to be a leap year (the textbook is still on page 5 1, "Do you know? "Why are there flat years and leap years? Because students are young and have limited knowledge, this knowledge should only be introduced to students as common sense. Teachers can combine example 2 with the following "do one thing" for teaching. Ask the question first: "February 28th every year, right? Ask the students to look at the February calendars of 2004 and 2005 with questions, and find out that there are 29 days in February 2004 and 28 days in February 2005. Next, students will observe the calendar of1993 ~ February 2004 in "Make a Work", think independently first, and then communicate with each other in groups. They can properly guide teachers who have difficulties and let each group talk about the observation results. Some students may say, "I have observed that the last line of February is 29 days." "Others said," I found that in every four years, there are 28 days in February in three years, and only 29 days in February in one year. "As long as the student's speech is reasonable, the teacher should give affirmation. Then, on the basis of summarizing the students' speeches, the teacher explained that a year with 28 days in February is called a flat year and a year with 29 days is called a leap year, and briefly introduced the judgment method of leap year. On this basis, let students calculate the number of days in a leap year by themselves and allow students to have different algorithms, and then discuss which calculation method is simple and what is the relationship between the average number of years and the number of days in a leap year. (3) Explanations and teaching suggestions on some exercises in exercise 12. Question 3: I really can't think of any other tips from the teacher for students to think for themselves. Question 5: The teacher can tell the students when next year is, and then let the students make their own monthly calendars. Question 7 is a birthday guessing game. Group activities can be arranged. A student puts forward a clue according to his birthday, such as "My birthday is one day later than the National Day." "My birthday and the party's birthday are the same day. "Wait, other students will calculate his birthday. Through this game, we can not only stimulate students' enthusiasm for learning, but also let them know some necessary social knowledge and the dates of major festivals. 2.24-hour timing method. Regarding the 24-hour timing method, the textbook is divided into two parts: first, by observing the rotation of the hour hand on the clock face, students realize that when 1 day is equal to 24 hours, they will use the 24-hour timing method to represent a certain moment; The second is to learn to calculate simple elapsed time, be more familiar with the 24-hour timing method, and know the difference between time and time. (1) theme map. The textbook shows a very familiar scene in students' daily life: a mother took her daughter to a department store. When she saw the sign at the entrance of the mall saying "Business hours: 9: 00 ~ 2 1: 00", the little girl couldn't help thinking, "When is 2 1: 00?" "This is a common problem in daily life, which leads to the discussion of the 24-hour timing method. Mom helped the little girl answer this question: "It doesn't close until 9 pm. "Next, the textbook introduces that in the time of 1, the hour hand just walked twice, indicating that 1 has 24 hours (the textbook is still on page 54," Do you know? "Introduce the history of the day to the students", so we often use the 24-hour timing method. Ask the students to observe the meaning of the number of outer rings on the clock face and the relationship between the number of outer rings and the number of inner rings on the clock face. Ask the students to find out through discussion that when the afternoon time or evening time is expressed by 24-hour timing method, 12 is added to the original hours, that is, 12 is added to the time indicated by the second circle of the hour hand. The following "doing something" is a connection problem. Here are three scenes of the little boy's day: sleeping, having lunch at school and coming home from school. The following are three moments expressed by the 24-hour system. Let the students connect one by one and get familiar with the 24-hour system. When teaching, I asked the little girl in the picture, "When is 2 1: 00? "Teachers can let students guess first and explain the reasons themselves. Students' answers may vary. They can also let students talk about "Where else have you seen this timing method", so that students can feel the close connection between mathematics and daily life and realize the importance of mathematics learning. At this time, let's guide students to explore the 24-hour timing method. Teachers can use the clock face as an intuitive teaching aid to demonstrate to students: on 1 (day), the clock goes exactly twice, from 12 in the evening to 12 at noon, and once it goes, it is 12 hours; From noon 12 to evening 12(0 o'clock), walking clockwise 1 is 12 hours, and a * * * is 24 hours, which is 1 = 24 hours. We call this timing method the 24-hour timing method. If conditions permit, students can do it themselves and intuitively feel that there are 24 hours a day. Then ask a question to the clock face: "What do the numbers on the outer circle mean? What does it have to do with the number of inner rings? " Let the students speak in groups after thinking, and the teacher will guide the students to speak, so that students can realize that when the clock goes the second turn, the number on the outer ring of the clock face is the time of 24 hours, and the difference between the number on the outer ring and the number on the inner ring is 12. Combined with the clock face, 9 am means 9 am and 9 pm means 2 1. Then ask the students to discuss "when is 24: 00 clock at 5: 00 p.m." and communicate after thinking for themselves. Some students may draw the conclusion that 5: 00 pm is 65: 438+07 according to the outer circle number opposite 5: 00 on the clock face; Some may also use 5+ 12 = 17 according to the relationship between the number of inner and outer laps. Finally, the teacher stressed that when using the 24-hour clock to indicate afternoon time or evening time, 12 should be added to the original time, that is, 12 should be added to the time indicated by the second circle of the hour hand. Next, let the students look at the clock face and be familiar with the 24-hour timing method. You can ask one student to turn the clock, and other students can tell the time. You can also ask the teacher to adjust the clock at any time. When you finish "doing" on page 53, the teacher can explain the contents of the picture a little. (2) Example 3. Example 3 Through teaching and calculating the simple elapsed time, students' understanding of the 24-hour timing method is deepened. This textbook is closely related to real life. By solving how long it takes to get from Beijing to Shijiazhuang by train, this paper introduces the problem of knowing the driving time and arrival time to find the elapsed time. Because these two moments are not unified timing methods, here we first show the clock face diagram corresponding to these two moments. Students can count the elapsed time by observing the clock face, or by observing the line graph under the clock face. Here, students are mainly required to observe the clock face and line segment diagram, turn two moments into 24-hour timing moments, initially understand the meaning of time and moment, and calculate the elapsed time with their mouths. Because the moments here are not the whole hour, they all contain complex numbers, and the calculation formula is difficult, so the calculation formula is not required, as long as students can directly calculate the elapsed time from the line segment diagram. In teaching, students can explore independently according to their existing life experience and then communicate in groups. When communicating, students will have doubts: the timing methods of these two moments are different. Why? At this time, with the help of clock teaching AIDS, teachers can ask students to dial the departure time on two clocks at the same time according to the meaning of the question, so that students can tell the corresponding time of 24-hour timing, and then use the demonstration method to turn the minute hand to the arrival time on the second plane from the departure time, so that students can observe intuitively and calculate the elapsed time orally. Teachers can also ask students to dial the departure and arrival times on two clocks respectively, and pay attention to the difference between the two timing methods when dialing. Then let the students think: How long does it take from Beijing to Shijiazhuang? Then discuss and communicate in groups. After the students speak, guide the students to express with a line chart, let the students observe the line chart and calculate the result with a clock face. If possible, students can operate by themselves and feel the elapsed time. (3) Explanations and teaching suggestions on some exercises in exercise 13. Question 1 is the mutual conversion between the two timing methods, which makes students more familiar with the 24-hour timing method. Question 2 requires the time to write each letter. If you add four hours to the last letter, there will be time for the next letter. Question 4 (1) is the time to convert conversion of time, which is open at night, into ordinary time method. Question 2 requires calculating the business hours of one day, and the business hours of noon and evening can be calculated separately first. Question (3) is an open-ended question. Students can ask "How long is it open at noon", "What time is it open at noon and at night" and so on. The solution to the fifth question (1) is: first, calculate how long you slept on the first day and the second day, and then find out how long you slept on the first day. I slept for 24-2 12 (24: 00) from 9:00(24:00) on the first night, and slept for 6 hours the next day. So I slept for nine hours. In question (2), 14: 30 is the start time of the activity, and 1 hour 20 minutes is the time of the activity. The start time plus 1 hour 20 minutes is the end time of the activity, which is 15: 50. Students with difficulties can demonstrate intuitively with the help of the clock model. Question 6, is the topic of connecting with practice. This is the train timetable. It is difficult to understand because there are many items. Teachers can give some guidance, using clock models and drawing lines to solve it. The running time is 9 hours and 7 minutes, 14 hours and 13 hours and 35 minutes respectively. Question 7 is to know the start time and elapsed time of the game and find the end time. First, change the elapsed time from 155 to 2: 35. Use 19: 30 and 2: 35, which equals 22: 05, that is, the game ends at 22: 05.