Πάνω στο γραφείο υπάρχει ένα μπλοκ και μια μολυβοθήκη με μαρκαδόρους.

Πάνω στο γραφείο literally means on top of the desk / on the desk.

• πάνω = up, on top
• στο γραφείο = on the desk / at the desk, depending on context

Greek often uses πάνω σε or πάνω + σε/article when it wants to make it clear that something is physically on the surface of something. So here, πάνω στο γραφείο is more specific than just στο γραφείο, which could sometimes mean at the desk rather than on the desk.

Because στο is the normal contraction of σε + το.

So:

• σε + το = στο
• σε + την = στην
• σε + τον = στον
• σε + τα = στα

This is extremely common in Greek and you should think of στο as a standard everyday form, not as something unusual or optional.

After σε, Greek uses the accusative case.

Here the noun is το γραφείο. For this neuter noun, the nominative and accusative forms are the same, so you do not see a visible change in the noun itself:

• nominative: το γραφείο
• accusative: το γραφείο

What changes is mainly the structure around it: σε το γραφείο → στο γραφείο.

So the form looks simple, but grammatically it is doing what Greek normally does after σε.

Greek word order is more flexible than English word order.

Starting with Πάνω στο γραφείο puts the location first, almost like setting the scene:

• Πάνω στο γραφείο υπάρχει... = As for the desk / On the desk, there is...

This is very natural in Greek. It is similar to how English sometimes says:

• On the desk, there is...

Greek often puts the place, time, or topic first if that is what the speaker wants to highlight.

This is a very common learner question.

In this sentence, υπάρχει works as an existential verb, like English there is. In Greek, when the verb comes first and is followed by a list of items, speakers often use the singular:

• υπάρχει ένα μπλοκ και μια μολυβοθήκη

The idea is that the sentence is introducing the whole situation as one existence statement.

If the noun phrase were clearly plural, Greek would normally use υπάρχουν:

• Στο γραφείο υπάρχουν μαρκαδόροι.

With two singular nouns joined by και, singular υπάρχει is very natural.

Because the indefinite article must agree with the noun’s gender.

• μπλοκ is neuter → ένα μπλοκ
• μολυβοθήκη is feminine → μια μολυβοθήκη

So the article changes according to the noun:

• masculine: ένας
• feminine: μια / μία
• neuter: ένα

This is one of the basic agreement patterns in Greek.

Yes. They are the same word.

• μια is the very common everyday spelling/form
• μία is a more careful or emphatic form

In ordinary modern Greek, μια μολυβοθήκη is completely normal and probably what you will see most often.

μπλοκ is a loanword and is often treated as largely indeclinable in everyday use.

In this sentence, it means something like a notepad or pad.

A useful point for learners: with words like this, the article often carries a lot of the grammar information:

• ένα μπλοκ
• sometimes plural: μπλοκ again, depending on usage

So even if the noun itself does not visibly change much, the article still helps show how it fits into the sentence.

Literally, μολυβοθήκη is something like a pencil holder / pencil container.

It comes from:

• μολύβι = pencil
• θήκη = case, holder, container

Depending on context, it can mean:

• a desktop holder for pens or pencils
• a pencil case

In this sentence, because it is on the desk and has markers in it, the most natural meaning is a pen/pencil holder sitting on the desk.

Because με takes the accusative case.

The basic noun is:

• ο μαρκαδόρος = the marker

Its accusative plural is:

• μαρκαδόρους

So:

• με μαρκαδόρους = with markers

This is a very important pattern to learn: many prepositions in modern Greek, including με, are followed by the accusative.

Because the sentence is talking about markers in a non-specific way.

• με μαρκαδόρους = with markers
• με τους μαρκαδόρους = with the markers, meaning specific markers already known from the context

So the version without the article sounds more natural if you just mean that the holder contains some markers, not a particular set already identified.

It most naturally describes μια μολυβοθήκη.

So the structure is understood as:

• ένα μπλοκ
• και
• μια μολυβοθήκη με μαρκαδόρους

In other words:

• a notepad
• and a pencil holder with markers

Greek often places a phrase like με μαρκαδόρους right after the noun it modifies, and that makes the connection clear. If the speaker wanted to express something broader, they would probably choose a different wording.