Now that we know the words for numbers, we will see how to express any date (month and day) in the Gregorian calendar. This system was adopted by China in 1912, right after the fall of the Qing1 Dynasty. (We will learn about the traditional Chinese calendar later, which is often referred to as the Xia4 Li4 or the Xia4 System, named after the very first Dynasty of which archeological evidence is yet to be found.)
We need to know the characters for month and day since a calendar date is expressed using the YYYY Year MM Month DD Day pattern.
The first day of a month is 一日, the fifth 五日, and so on. What about the eleventh? It’s simply 十一日. And 二十三日? Yes, it’s the 23rd.
Congratulations! You’ve just learned how to express a day in a month and a number less than one hundred as a bonus. It’s so simple, right? What is more: There is no need to learn new words for the twelve months, or 十二ge4 月. (Plus, there is normally no plural form in Chinese; instead, a count word like ge4 is used.) The twelve months are simply 一月, 二月, ..., 十月, 十一月, and 十二月
To put it together, New Year’s Day is 一月一日, Christmas 十二月二十五日, Halloween 十月三十一日, and April Fool’s Day 四月一日.