How to use “日” and “号” properly

[Do you know?]

Both the characters "号" (hào) and "日" (rì) can be used to express a date. Is there any difference between them?

[Definition Differences]

号: mark; order; size or grade

日: sun; day; daily; daytime; a certain time

[Uses]

"号" and "日" can replace each other only when a date is expressed. For example, "十月一号是中国的国庆节 (shí yuè yī hào shì zhōnɡ ɡuò de ɡuò qìnɡ jié)", or "十月一日是中国的国庆节 (shí yī yuè yī rì shì zhōnɡ ɡuò de ɡuò qìnɡ jié)", both of which mean "Oct. 1st is the National Day of China". In other cases, they cannot be exchanged.

Examples:

In the following sentence, "号"cannot be replaced by "日".

我穿三十五号的鞋子。(wǒ chuān sān shí wǔ hào de xié zǐ)

My shoe size is 35.

In the following sentence, "日"cannot be replaced by "号".

这个问题我们改日再谈吧。(zhè ɡe wèn tí wǒ men ɡǎi rì zài tán bɑ)

Let's talk about it in another day.