People write dates in different ways, but there are two very strong conventions which are currently applied, one for British English and one for American English. In American English you write

whereas in British English the numbers are more clearly separated:

Note that no comma is used in the British English version.
     A recent trend is to write dates as they are spoken. An example would be the 16^th of July rather than just 16 July. While this usage is gaining ground, we advise you to avoid it in formal writing.
     One final thing to note about dates is that the specifications st, nd, rd and th are gradually disappearing in British English. We advise you to follow the trend and keep dates simple.