The Night of the Sevens occurs on the seventh day of the seventh lunar month. It is typically in August on the Gregorian calendar. 七 (qī) is the Chinese character for "seven." 夕 (xì) is the radical that means "night." To fully appreciate the Night of the Sevens, here is the story of the Cowherd and the Weaver Girl: A long time ago, there was a young cowherd 牛郎 (niú láng). Niu Lang was poor and his only companion was his old ox. He did everything with his ox, but Niu Lang still felt lonely. Up in heaven, there was a weaver girl 織女 (zhī nǚ). Zhi Nu had six older sisters, making her the seventh daughter. Her role was to weave cloth, which are the clouds mortals see in the sky. Zhi Nu sometimes got bored, so she would go down to earth. During one of these visits, she met Niu Lang. They quickly fell in love and got married. They had two children, a son and a daughter, and lived happily together for ten years.
Eventually, the Queen Mother of the West 西王母 (xī wáng mǔ) found out about their marriage. She was furious that Zhi Nu neglected her job for so long. One day in heaven was ten years on earth. The Queen Mother took Zhi Nu back to heaven. Niu Lang, with their two children by his side, tried to follow Zhi Nu to heaven. The Queen Mother was furious and created a large silver river 銀河 (yín hé) in the sky, also known as the Milky Way.
The magpies around the world felt bad for the lovers. Once a year, they formed a magpie bridge 鵲橋 (què qiáo), allowing Niu Lang and Zhi Nu to meet. For this reason, the Night of the Sevens is also known as Chinese Valentine's Day or the Magpie Festival. The story of the Cowherd and the Weaver Girl is nicely represented in the summer night sky. Vega is the brightest star and high in the sky in the late summer, so Vega is Zhi Nu. On the other side of the Milky Way is Altair, representing Niu Lang. If you look closely, there are two stars on either side of Altair, symbolizing Niu Lang and Zhi Nu's children. Along with Deneb, Vega and Altair form the summer triangle. In some versions of the story, Deneb was a fairy who helped Niu Lang and Zhi Nu meet every year. If it rains on this day, they are tears of joy from heaven. Like Valentine's Day, Chinese Valentine's Day has become heavily commercialized. In the past, girls would use this day to show their domestic skills, such as melon carving and embroidering.
Most of the time, zero is simply written as 0. 兩 (liǎng) is used to represent the number 2 in certain circumstances.
And that's all you really have to know! Some people believe Asians are better at math because the numbering system is logical and consistent.
Examples:
17 = 10 + 7 = 十七
52 = five 10s + 2 = 五十二
394 = three 100s + nine 10s + 4 = 三百九十四
2000 = two 1000s = 兩千
Random Fact: 4 and 10 are considered unlucky because they sound like the Chinese word for die/death 死 (sǐ)
月 is also the character for moon, since a month is based on the moon's orbit.
Examples:
February = 二月
2001 = 二零零一 年
July 31, 1995 = 一九九五年 七月三十一日
Examples:
2:00 = 兩點
4:15 = 四點十五分
5:30 = 五點三十分 or 五點半 (bàn) where 半 means "half"