When a primitive man first realized 1+ 1=2, and then realized that two numbers were added to get another definite number, this moment was a great moment of human civilization, because he discovered a very important property-additivity. This property and its extension are the whole foundation of mathematics. It even tells us why mathematics is widely used and its limitations.
As we all know, there are three different things in the world. One is the quantity that completely satisfies additivity. Such as mass, the total mass of gas in a container is always equal to the sum of the masses of each gas molecule. For these quantities, 1+ 1=2 is completely true.
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Physical World, a famous British scientific magazine, held a unique selection activity before, inviting readers from all over the world to choose their greatest and favorite formulas, theorems or laws. To the surprise of many people, the basic mathematical formula 1+ 1=2, which is known to primary school students, was not only selected, but also ranked first.
A Canadian reader gave his reason: "This simplest formula has a wonderful aesthetic feeling." The host of this selection activity commented: "The power of the great formula is not only to explore the basic characteristics of the universe and convey symbolic information, but also to nurture more nature as much as possible.
Baidu Encyclopedia-1+ 1=2