First we must know how to say NUMBER in Chinese:
1 = 一　(yī)
2 = 二　(èr)
3 = 三　(sān)
4 = 四　(sì)
5 = 五　(wŭ)
6 = 六　(lìu)
7 = 七　(qī)
8 = 八　(bā)
9 = 九　(jĭu)
10 = 十　(shí)

Pay attention these Notes:
1.When“2”+ measure words,it usually pronounced “liǎng”
For example：liǎng bēi shuǐ 两杯水-two cups of water
                    liǎng gè xīguā 两个西瓜-two watermelons

2.Start with “200”，“2” also pronounced “liǎng”
For example：liǎng bǎi（200） ；liǎng qiān（2000） ；liǎng wàn（20,000）。

3.When "1" in the room number,filght number,bus number,plate number,it usually pronounced“yāo”
For example:"yāo wǔ yāo liù "hào fáng-1516号房-Room 1516
  “Shēnzhèn hángkōng ZH jiǔ bā èr yāo-深圳航空ZH9821-Shenzhen Airline ZH9821

Just like people all over the world, people in China traditionally associate luck with various things and numbers. If you remember this, you will gain an understanding of Chinese manners and customs and will not embarrass yourself or your Chinese friends.

As a rule in day-to-day life in China, it is customary to regard even numbers as being more auspicious than odd numbers. In China, traditionally gifts are given as a part of the celebration for all occasions. Thus, guests will always give even-numbered presents. As the number two (Er), usually suggests germination and harmony, at wedding celebrations, decorations are invariably setout in pairs: a pair of red candles, a pair of pillows, and couplets hung on two sides of the hall. Six, pronounced as 'Liu', conveys indirectly its homophony's meaning – Do everything smoothly; and eight, 'Ba' in Chinese has a similar sound to 'Fa', which means to make a fortune. All business men favor this number very much. However four, is the exception to the even number rule as it sounds like 'Si' (death). So when people choose car license tags, phone numbers, and room numbers, they try to avoid it.

For odd numbers, seven implies anger and abandon, but nine, sometimes means longevity and eternality.

based on these notions, it is the fashion for young lovers to send roses. One rose represents that 'you are my only love'; two, 'only we two in the world'; three, the three moving words 'I love you'; and nine, 'everlasting love'. The Chinese zodiac is also related to lucky numbers, as well as 'fengshui', a set of principle to the layout of furniture and the structure of the house.