What is the significance of number 5 in China?

Among the Chinese, good fortune comes from five blessings: long life, luck, wealth, health, and peace.

http://www.goodluckcreations.com/luckynumbers.html

The number five holds tremendous significance in nearly all Buddhist traditions. It refers to the Five Colors (五色), the Five Senses (Goshiki 五識), the Five Wisdoms (Gochi 五知), the Five Buddha (Gobutsu 五佛), and a host of other important philosophies. The number five is intimately associated with the Chinese theory of the Five Elements, a concept underpinning the Zodiac Calendar, the latter serving as the preeminent calendar of old-world Asia. Indeed, China's five-element theory is generally thought to predate Buddhism, but in later centuries its influence is dressed predominantly in Buddhist garb. There are dozens of concepts associated with the number five.

Visit this link for more interesting details.
http://www.onmarkproductions.com/html/number-five.html

Just 5 spoonfulls of melamine makes the medicine go down
In the most delightful way!

the 5 elements: metal, wood, water, fire, earth.

These 5 elements are the basis of many ancient philosophies (including fung shui), as well as traditional medicine.

In feng shui, the goal is to achieve a hamonious balance between the 5 elements. This is the same for fortune telling. For example, when a baby is born, parents will take his birth date and time to the fortune teller. He will then determine the imbalance of the elements so that parents can then select a name that restores the balance.

In traditional medicine, the 5 elements govern the 5 most important organs: heart, liver, spleen, lung, kidneys. Fire is red, which is also the excretion from the heart, so fire = heart, and so forth for the other elements.

Lucky.