Cut out circles of different diameters from paper and show that the area occupied by the mixed circles is less than the sum of the areas occupied by these circles separately.
The area occupied by the mixed paper circles is less than the sum of the areas occupied by these circles separately, because in the first case, some circles partially overlap.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.