1, using food decomposition.

2. For example, there are five fruits in the basket, one on the plate and the other four on the plate.

3. Let the children find that 5 can be divided into 1 and 4.

4. Similarly, 1 and 4 can form 5.

5 and 5 can be divided into 2 and 3, 3 and 2, 4 and 1.

Extended data:

Mathematics teaching methods play an important role in stimulating students' interest in learning mathematics, realizing the purpose of mathematics teaching and improving the quality of mathematics teaching.

Commonly used mathematics teaching methods include: inspiration, explanation, dialogue, practice, discussion, demonstration, practice, observation, review and so on. Among them, inspiration, explanation, dialogue and practice are used more. At present, the experimental mathematics teaching methods at home and abroad are: discovery, research, self-study guidance, program teaching, optimization teaching, algorithm teaching, "reading, discussing, speaking and practicing" and so on.