Look, what did the teacher bring you today? (A bag of candy) I want to reward the students who listened carefully, observed carefully and thought positively today.
Activity 1 Count Activity (Count) Count Activity (Count)
1, can you guess how many pieces there are in this bag of sweets?
Students have all kinds of ideas. What should we do if we want to know how many sweets are in the bag? (Count) Then let's count how many sweets we have together today. (Blackboard: How many sweets are there)
In order to make it convenient for students to count, we use disks instead of candy. The number of discs in the students' hands is the same as that in the teacher's bag. Now please count quickly! (Number of students)
4. Who can introduce the number method to you?
It seems that students have all kinds of counting methods, all of which are counting the number of sweets. Let's look at these counting methods again. (Courseware demonstrates various mathematical methods)
6. Students, come and look at these figures. What did you find? (Name)
7. (Play the courseware while talking) We counted 1 block and 1 block 20 times. Let's count them together. Two dollars, two dollars. How many times do you need to count? What about five dollars and five dollars? How many times? 10. 10? How many times will it take? Please have a look. What did you find? (Student: The number of counts is different) The more blocks you count each time, the fewer times you count, and the fewer blocks you count each time, the more times you count.
Activity 2 Count activities (two numbers)
1. Teacher, there are other sweets here. Let's have a look. Look carefully. What do you think of the arrangement of these sweets? (health: neatness)
2. "Horizontal counting"
It's really neat. You see (the teacher pointed sideways), how many are so neatly arranged? How do you calculate it? (Student: Counting horizontally) He counts horizontally like this, and there are seven in a row. In mathematics, counting horizontally like this is called counting by rows. Please reach out your hand and do it with the teacher. (Teachers and students point sideways with their hands) Because there are 7 pieces in each row, we call it 7 pieces in each row. How many lines are there? (second line) What about the * * * organic block? Can you say it again in this language? Courseware demonstration: each line has a block, a line and a block. )
3. "vertical counting"
(1) We just counted horizontally, and we know that it is by line. What else can it be? (Student: Count vertically) How to count vertically? The method of counting vertically like this is mathematically called counting by column.
(2) Can you count the pictures column by column again? (Show new drawings) 4 pieces in each column, 3 columns, one * * * 12 pieces. Who will say it again in this language? Courseware demonstration: each column has a block, a column and a block. )
Activity 3 Activity Count Activity (three numbers)
1. Please observe "look horizontally" or "look vertically". What can you find?
2. By counting horizontally and vertically, we can calculate the quantity accurately. Can these two numbers be expressed by formulas? Please open the book on page 16 and write the method of horizontal counting here and the method of vertical counting here. (courseware description)
Tell me how you worked out this formula. (blackboard maps and formulas)
Vertical number, how many 3s are there? (Health: 5 3) Can you order? (For every 1 3, the teacher posts 1 3. )
This formula is calculated horizontally, and several 5s add up to a point. (When the teacher posts it, the students order it)
4. The students listed two different formulas by their own numbering methods. What are the characteristics of the two formulas? (Name) If the formulas are different, how can we get the same number? (Student: One is the number five of five, and the other is the number thirteen of three) You have discovered all the secrets in the small formula. It's like the same picture, counting horizontally and vertically, the result is the same.
Activity 4 Activity expansion
1, the students counted so well that the little frog joined in. He wants to play checkers with us. (Show/kloc-question 4 on page 0/7) Did you see how the little frog jumped? (Born in a book)
This little frog is so naughty that it jumps on the teacher's ruler. He wants to jump three squares, so our formula will keep adding up. Is there a better way? If only we could have a simpler method, which we will learn next class.