话说在数学山集合寨有一伙人马,它们可 以称得上英雄好汉．它们当中全集为老大,坐 头把交椅,其后依次是老二子集、老三交集、老 四并集和老五补集． 却说这大哥全集斋心人厚,有海纳百川之 肚量．你就看它相貌堂堂,双手一举,显现出欢 迎各路英雄的形象(用∪表示)． 再说这老二,人虽没什么本事,却也与人 为善．它对长辈忠心耿耿,只要人家同意的它 也没意见．你看它的名字和形象((?))就知道 了,顺顺从从． Saying that there is a group of men and women in Mathematical Mountains, they can be called Heroes. Among them, the complete set is the oldest, sitting in the top spot, followed by the second oldest son, the oldest third oldest, the oldest fourth old and the fifth oldest. It is said that this big brother is full of people and is full of people. You see it looks good, hands in one fell swoop, and it shows the image of the heroes who welcome each hero (indicated by ∪). In addition to this second child, although people do not have the ability, but also with people for good. It is loyal to the elders and as long as people agree it has no opinion. You see it’s name and image ((?)) and you know it.