我们计数物体的个数,便得到了自然数,这是数的概念的最初的形成。然而要完整地完成自然数的概念,还必须有一个确定的读法和写法,即对每一个自然数,必须用一个名称读出来,用一个符号写出来。但是自然数有无限多,要用无限多个不同的名称和符号来表示它们,那是非常不方便的,也 We count the number of objects, we have a natural number, which is the concept of the number of the initial formation. However, to complete the concept of natural numbers, there must also be a definite way of reading and writing, that is, for each natural number, it must be read out by a name and written by a symbol. But there are an infinite number of natural numbers, and it is inconvenient to use an infinite number of different names and symbols to represent them.