Τα τουβλάκια είναι κάτω από το τραπέζι και λείπει ένα κομμάτι από το παζλ.

Τα is the definite article the for neuter plural nouns in the nominative or accusative. Since τουβλάκια is neuter plural, it takes τα.

So τα τουβλάκια means the blocks.

Yes. The singular is το τουβλάκι, and the plural is τα τουβλάκια.

It comes from τούβλο meaning brick, with the ending -άκι, which often makes a word smaller or more familiar. In everyday Greek, τουβλάκι often just means small block or building block, especially a toy block. It does not always sound especially cute in context; it can simply be the normal word.

In Greek, the verb είμαι has the same present-tense form είναι for both:

• he/she/it is
• they are

So είναι can mean either is or are. The subject tells you which one it is.

Here, the subject is τα τουβλάκια, so είναι means are.

Κάτω από is a very common Greek expression meaning under or below.

• κάτω by itself means down or below
• από often means from, but with κάτω it forms the fixed expression κάτω από

So you should learn κάτω από as a unit meaning under.

Yes. Από normally takes the accusative case.

The noun τραπέζι is neuter, and in the singular its nominative and accusative forms look the same:

• nominative: το τραπέζι
• accusative: το τραπέζι

So the case is accusative here, even though the form does not visibly change.

Here λείπει means is missing.

The verb is λείπω, which can mean that someone or something is absent or missing. In this sentence, Greek is phrasing the idea as:

a piece is missing from the puzzle

That is why the verb is attached to ένα κομμάτι.

Because its subject is ένα κομμάτι, which is singular.

The sentence has two parts:

• Τα τουβλάκια είναι κάτω από το τραπέζι
• λείπει ένα κομμάτι από το παζλ

In the second part, the subject is not τουβλάκια. It is ένα κομμάτι. Since ένα κομμάτι is singular, the verb is singular: λείπει.

If it were plural, you would say:

Λείπουν δύο κομμάτια = Two pieces are missing

Greek word order is more flexible than English word order.

Λείπει ένα κομμάτι is a very natural way to present new information. It is a bit like saying There is a piece missing or A piece is missing.

You could also hear:

• Ένα κομμάτι λείπει
• Από το παζλ λείπει ένα κομμάτι

These are all possible, but they shift the emphasis slightly.

Yes, but its role is a little different here.

In κάτω από, από is part of the fixed expression under.

In ένα κομμάτι από το παζλ, από keeps more of its usual idea of from: it is a piece from the puzzle, meaning a piece that belongs to that whole.

In English, you might often say a piece of the puzzle, but Greek very naturally says κομμάτι από το παζλ in this kind of context.

Παζλ is an indeclinable borrowed noun in Modern Greek. That means the noun itself usually stays the same, and the article or preposition shows its grammatical role.

So you get forms like:

• το παζλ
• από το παζλ
• στο παζλ
• του παζλ

The word παζλ itself stays the same.

Yes, absolutely.

Both are possible:

• ένα κομμάτι από το παζλ
• ένα κομμάτι του παζλ

Very roughly:

• από το παζλ often feels especially natural when you are thinking of a piece as coming out of, missing from, or taken from the whole puzzle
• του παζλ is a straightforward of the puzzle

In this sentence, ένα κομμάτι από το παζλ sounds very natural because the idea is that a piece is missing from the puzzle.