Breakdown of Það er ein baun eftir á disknum.
vera
to be
það
it / there (existential) / the one (n)
einn
one
á
onto / on / in (static location) / on (a day of the week)
Questions & Answers about Það er ein baun eftir á disknum.
Why does eftir mean 'left' here when it usually means 'after'?
As a preposition, eftir does mean 'after'. But in this sentence, it is used as an adverb meaning 'left' or 'remaining'. Using eftir is the standard way in Icelandic to say that something is left over or still there.
Why do we use ein instead of einn or eitt?
The number one changes its ending to match the gender of the noun it counts. Because baun (bean) is a feminine noun, we must use the feminine nominative form ein.
Why is disknum in the dative case here?
The preposition á (on) governs the dative case when it describes a static location where nothing is moving to a new destination. Since the bean is simply sitting on the plate, we use the dative. If someone were putting the bean onto the plate, á would take the accusative case instead.
How do you get disknum from the dictionary word diskur?
First, the masculine noun diskur (plate) changes to diski in the dative case. Then, you attach the dative masculine definite article -num (the) to the end. The final -i in diski is dropped when the article is added, resulting in disknum.