How do I use the dual case in Arabic?

OK. The Arabic dual, part 1!
The Arabic dual is not something to fear! It is a beautiful construction that allows you to refer to two nouns - not just one or more than one as we are restricted in English. And it is easier than most Arabic constructions!
There are two possible endings for the dual case. These are: ان- (an) and يَن- )ayn. Note the fatha above the ى which differentiates the ending from the standard plural ending ين- (iin).
Which you use will depend on the case of the word. For now, we will look at ان- which is used only for the nominative.
An example is helpful at this stage:I have two books in my bagلدي كتابان في شنتتي
Importantly, adjectives must agree with the noun. Therefore:I have two large books in my bagلدي كتابان كبيران في شنتتي
If the noun is feminine dual, the taa marbuta (ة) 'opens up' and becomes a simple taa (ت). Then you put the dual ending on!There are two schools in this cityهناك مدرستان في هذه المدينة Finally, if the dual noun is in an idaafa construction, or has a pronoun suffix then the nuun (ن) is dropped. Hence:The two university students are present in the libraryطالبا الجامعة موجودان في المكتبة