Equal division is a mathematical activity in life, which is exploratory. Children like to divide snacks, toys and school supplies themselves, and often ask teachers for help because of unfair distribution. When designing bisection mathematics activities, we should attach importance to children's original experience, give full play to children's initiative, let children explore the method of bisection of objects with different shapes independently, and realize cognitive balance and development in the interweaving of new requirements and old experience.

moving target

1, let children learn to divide an object into two parts, knowing that part is smaller than the whole and the whole is larger than the part.

2. Let children use dichotomy knowledge to solve problems in life and experience the joy of success.

Activities to be prepared

1. Material paper: round, pentagonal, heart-shaped, parallelogram, flower-shaped and tree-shaped.

2. Physical objects: peanuts, ginkgo, red dates, etc.

3. Courseware production: a new biography of Stupid Bear, and a diagram of the relationship between parts and the whole.

Activity process

1, equal initial contact.

Appreciate the story "The New Biography of Stupid Bear".

Mother bear has two children, one is big black and the other is little black. One day, two brothers found a delicious bread. Big black is afraid that little black will eat more, and little black is afraid that big black will eat more. Just then, Aunt Fox came and helped them divide the bread into two pieces. When the two brothers saw it, they shouted, "No, no, one is big and the other is small." Aunt Fox said, "Don't worry, this big one." I will bite it. "When the two brothers saw it, the big one became smaller and the small one became bigger. They cried out in a hurry:" No, no, one is big and the other is small. "... In this way, Big Black and Little Black only ate a little bread and didn't know that they had been taken in by the fox.

The teacher asked, "If you were asked to help, would you divide it?" ? How can I divide it into two pieces of bread of the same size? "

The teacher provided round paper and guided the children to find ways to divide it into two equal parts. Child operations.

"Who will tell you how to divide? How do you prove that your share is the same? " The teacher encourages young children to think of various ways to prove it.

Teaching Assumption: Using the questions in the story, the topic of inquiry is skillfully led out, so that children can enter the learning scene in a natural state and have a strong thirst for knowledge, and then start with a simple bisection to create a relaxed environment for children to further explore. )

2. Divide several figures in different ways.

The teacher said, "The teacher has prepared various graphs for you. Please try to divide them into two equal parts. "

Children's operation, teachers participate in group activities, encourage children to explore various points of the figure.

(Teaching assumption: Rich materials contain different exploration results, which also provides the possibility for children to explore independently. )

3. Understand the relationship between the whole and the parts.

(1) communicate in groups and encourage children to speak out their opinions in groups.

(2) Collective communication, first

Let the children talk about various ways to divide squares equally.

The teacher asked, "Who will tell us how you divided the square into two equal parts?" . How to prove that these two copies are the same size? Who else divided the square into two parts in different ways? "

Courseware display record:

Overlapping verifications have the same size, and operations that are not split in two are deleted.

The communication and discussion of other graphics are the same as those of boxes.

The teacher concluded: "By folding in half, we divide these figures into two parts with the same size, which is equal division."

(3) Teachers and students cooperate with each other to explore other methods of dividing squares.

The teacher provides each group with a foam box, and asks the children to put it on it with a small stick and divide it to see if it can be divided into two halves, not diagonally and not centered on the edge.

The teacher helps to verify according to the child's operation.

(4) Guide children to understand the relationship between the whole and the part.

Teacher: "We just divide the circle, square and heart into two parts with the same size in different ways. Let the children see which is bigger than the original picture (courseware demonstration). Which is smaller? What was the original number? (half) "

(Teaching assumption: After children gain some perceptual knowledge through operation, teachers should help children distinguish between the true and false things and complete the leap of understanding. Here, the teacher guides the children to exchange and discuss, and summarizes the answers from the children's answers. Teacher-student interaction and student-student interaction have important educational value. )

Step 4 solve new problems

(1) Ask new questions.

The teacher asked: "bread 1 piece, snacks 1 piece." The two brothers share it, and each eats only half. " . If there were two snacks and two pieces of bread, how much would each bear eat? If there are four dates, how many do the brothers eat each? "

(2) dividing objects.

The teacher provides peanuts, ginkgo, red dates and so on. , so that children can be divided into two parts.

Tell your child that there is an ingredient of eight-treasure rice in each box. Two children sitting next to each other dressed up as bears. We put these ingredients together and then check them with each other to see if they are the same.

Teaching assumption: The primary education of children's mathematics focuses on stimulating their cognitive interest and desire to explore, so that they can experience the fun of exploration and success. This process is closely related to children's lives, guiding children to use knowledge and cooperate to solve practical problems. By transforming knowledge into ability, children will be able to experience the ease and fun of math activities. )