Historically, there have been two regulations at home and abroad about whether 0 is a natural number: one stipulates that 0 is a natural number, and the other stipulates that 0 is not a natural number. Since the founding of the People's Republic of China, the textbooks of primary and secondary schools in China have always stipulated that the set of natural numbers does not include 0.

At present, most foreign mathematicians stipulate that 0 is a natural number. In order to facilitate international exchanges, national standards stipulate that natural number set includes 0. Therefore, in our newly published textbooks, this treatment is carried out in accordance with national standards, and the original natural number set is now called positive integer set. At the same time, we also use some mathematical symbols according to the national standards.

From the point of view of use, it doesn't matter much whether the set of natural numbers contains 0. As ordinal number, starting from 0 is the same as starting from 1; We used to say n∈N, now we just need to say that n is a positive integer.