Beijing Normal University Edition Mathematics Grade One Volume 2 Unit 3 Lesson 4 Who has more red fruits?

Teaching objectives

1. Make students learn to compare the sizes of numbers within 100 and experience the method of comparing the sizes of two numbers.

2. Through watching, comparing and speaking, cultivate students' ability to observe and compare, as well as the ability to ask and solve problems.

Teaching focus

Compare the size of numbers in 100.

Teaching difficulties

Master the method of comparing the size of numbers.

teaching process

First, introduce a conversation

Teacher: Students, do you know what season it is?

Health: Spring.

Teacher: Yes, spring is full of flowers, which is a good time for sightseeing.

(PPT shows pictures of spring)

Teacher: Bears and monkeys meet and play in the park. Look! Did they have a good time?

Health: Happy!

Second, explore new knowledge.

Looking for information

(PPT3: Theme Map)

Teacher: What else do you find in the picture?

Answer, paste animal heads and write math information on the blackboard.

(2) Problem analysis

Teacher: Do bears and monkeys have as much red fruit?

Health: Not so much.

Teacher: Who has more red fruit?

(The teacher writes on the blackboard)

Teacher: To know who has more red fruits, we must first compare the sizes of 2 1 and 18.

Teacher: How do these two figures compare? Is there any good way?

(3) Inquiry method

Teacher: Think about it first.

(Give students time to think)

Teacher: Raise your hand if you think of a way! The response of these students is really quick and good! Try to say your method out loud, and I'll listen. For those students who haven't figured out a way, it doesn't matter. I can help you with the school tools around you, and I can also study with my deskmate. Let's start now!

(Guidelines for District Patrol)

Communication method

Teacher: We had a very serious discussion just now. Who wants to tell you how you compare 2 1 and 18?

Health 1: first count 18, then count 3 to 2 1, so 2 1 is greater than 18. (blackboard writing)

Health 2: 2 1 is greater than 20 and 18 is less than 20, so 2 1 is greater than 18. (blackboard writing)

Health 3,4: replacing red fruits with sticks, it is found that 2 1 has two bundles of sticks 1 more, while 18 only has 1 bundle, so 2 1- 18.

The decimal digit of healthy 5: 2 1 is 2, which means two tens. The seven digits of 18 are 1, which means 1 10, and two tens are greater than 1 10, so 2 1 is greater than/kloc-0. (blackboard writing)

Health 6,7: Dial the numbers 2 1 and 18 on the counter first, and then compare them on the counter: there are two beads on the tenth number of 2 1, indicating two tens, and there is a bead on the tenth number of 18, indicating 1 tens.

Health 8: 2 1- 18 = 3, so 2 1 is greater than 18.

Health 9: First compare the ten digits of these two numbers, one is 2, the other is 1, and 2 is greater than 1, so 2 1- 18.

(blackboard writing)

Teacher: The students showed so many methods, no matter whether you use sticks, counters or numbers, or even directly observe and compare 2 1 and 18. What is the actual comparison?

Health: The tenth digit.

(The teacher emphasized 2 and 1 with colored pens. )

Teacher's guidance summary: there are more than ten places, and this number is large.

(5) Comparison: 32 and 34.

Teacher: The little monkey lost the game, but he was not convinced.

(PPT plays monkey: wearing red fruit is not my strong suit. If I count with a counter, I will definitely win! Look, show me the counter)

Teacher: What are these two numbers? (Answers 32 and 34 on the blackboard)

Teacher: How to compare 32 and 34?

Health: Because 2 is less than 4, 32 is less than 34. The teacher emphasized the difference between 2 and 4 with colored pens.

Teacher: What is he comparing?

Health: He compared the figures.

Teacher: Why do you want to compare the numbers in the unit?

Health: Because the ten digits of these two numbers are the same, they are all 3, so we should compare the digits.

(6) Comparison: 100 and 99.

Teacher: The little monkey really won this time. He is very proud! I quickly pulled out a lot of beads on the counter (PPT shows the number of little monkeys pulling out) and only left one for the bear (PPT shows one bead). Unexpectedly, the bear won. How did it do it?

Health: The little monkey pulled out 99, and the little bear put that bead in the hundredth place. This number is 100.

Teacher: Do you think the same as him?

Health: The same.

Teacher: How do you compare these two figures?

Health: 99 is a two-digit number, 100 is a three-digit number, and three digits are greater than two digits.

(seven) recall methods, induction and summary.

Teacher: Now let's review the figures we just compared.

100 > How do you compare these two figures?

2 1 & gt； What is the comparison method of 18?

32< What about this group of 34 people?

(PPT plays the little monkey: Students, you are so smart! If you compare sizes in the future, what can you do to win? Can you teach me? )、

Tell me how to compare the sizes.

Teacher: As everyone said just now, the more digits, the bigger the number. If the number of digits is the same, the number on the highest digit is large, and if the highest digit is the same, the number is large. If they are the same, compare the next digit.

Third, consolidate practice and expand extension.

Teacher: We summarized this method. Let's try some questions!

(1) Specific dimensions. Title 1 on page 29 of the textbook.

Teacher: Please finish the exercise 1 and compare the sizes.

(PPT shows problems 1)

Students finish independently, and teachers patrol and guide.

Name the results and compare them.

(2) fill in the comparison.

(PPT plays the little monkey: The students have learned so well that I will test you with a line chart! )

(PPT shows a digital line chart)

(PPT plays little monkey: What did you find? )

Think and answer.

Teacher: The number closer to the left is smaller, and the number closer to the right is bigger.

Teacher: So numbers greater than 45 are on the right of 45, and numbers less than 90 are on the left of 90.

(3) fill in. Question 2 on page 29 of the textbook.

Teacher: Can you write the answer accurately without the line chart? Please complete the second question of "Practice".

Do it independently and name the result.

(d) Games: Compare the number of dials.

Teacher: It seems that everyone has mastered the comparison of size skillfully. How about we play a game of "comparing numbers and sizes"?

(The students scrambled to raise their hands, and the teacher named one. )

Teacher: Let's get rid of a number first.

The teacher makes a gesture of quietly pulling a number, and the students pull a number. )

Teacher: Pull it out and compare it.

(Teachers and students show counters at the same time)

Teacher: Next, two people at the same table play.

(5) Company by company. Question 3 on page 29 of the textbook

Independently completed

(6) ancient people. Question 4 on page 29 of the textbook

Independently completed

(7) "size" in life.

Teacher: Today we learned to compare numbers in class. Can anyone give an example of "comparing sizes" in life?

Fourth, the class summarizes.

Teacher: Everyone spoke very well just now. Let's recall, what did you learn in this class?

Name 2-3 students and say

Teacher: The teacher sorted out the methods summarized by everyone into "Comparing Children's Songs" and read it. (PPT shows children's songs)

Verb (abbreviation of verb) after-school investigation

Teacher: I hope the students can apply what they have learned today to their lives! (PPT shows a small survey)

Teacher: Please investigate how many classes there are in Grade One in our school after class. Find out which class has the largest number of students by comparing the number of students in each class. Which class has the smallest number of students?