Number meaning is closely linked to culture. Here are some examples for you. 1. Number 2(er, the fourth tune)---- now is a popular adjective among netizens and close friends. It means stupid but in a friendly way without offense. Like a joke. 2. Number 3 is nothing special in Chinese mainstream society. 3. Number 4 is an unlucky number because its pronounciation is similiar to 死 ( si, the third tune) that means die. 4. Number 8 is a lucky number because its pronounctiation is similiar to 发 (fa, the first tune) that means going to have wealth (发财 to going to own wealth). 5, Number 9 has the same pronounciation with 久 that is an adjective and means that something good lasts in/during a long time. 6. Number 10 usually is a symbol as prefection because 10 is the last number of a number cycle. Two cases: 1. Chinese will not choose the 18th floor because in Chinese culture, there are 18 floors in hell and the 18th is the most serious. 2. As what i mentioned, Chinese always avoid number 4. Attention please! All these above are based on culture of Southern China and on culture of 汉族, major nationality of China.

3 is ok, 5 is not

numbers may have different meanings due to different local cultures, mostly we relate them to our dialects, so all these meanings are just inside ones

as other things of our life, numbers are closely to our daily life, that's to say, different numbers are selected to work with different applications or situations, i may give you some examples, people choose a number for their tag of the vehicle or a cell-phone number, they try to stay away from "4", as the pronunciation of which appears like" death" in Chinese, 1-3-5-7 are not welcome in the wedding ceremony as they are "single" (odd numbers, not "couple" ), however, as an odd number, 9- is popular to people everywhere in China as it stands for long-lasting, forever, etc...2-0 are okay with people, we are not picky, 6-8-0 are top 3 favorite numbers to most Chinese. Well, as the times go by, more and more young generations are not that much about numbers, this is what's happening, i am not saying it's right or wrong.

How serious are we Chinese about numbers and their meanings? It's a tricky question. Generally speaking, it depends. Take myself as an example, I don't care much about the numbers. But for some, different numbers do mean a bit. For instance, some of my friends would frown if people say 4 or similar pronunciation on a happy occasion, such as wedding parties or housewarming party. And basically, Chinese prefer 6 and 8, since 6 is believed to mean "things would go smoothly" and 8 stands for prosperity. As for the other numbers, I don't think Chinese care a lot.