Ο λογιστής και η λογίστρια συμφωνούν ότι το τιμολόγιο είναι σωστό και δεν λείπει τίποτα.

Greek often has different masculine and feminine forms for professions and roles.

• λογιστής = male accountant
• λογίστρια = female accountant

The articles match too:

• ο λογιστής
• η λογίστρια

So the sentence is explicitly talking about one man and one woman.

Because Greek normally uses the definite article with specific people, and each coordinated noun keeps its own article.

So:

• ο λογιστής και η λογίστρια

is the natural way to say the accountant and the female accountant / the male accountant and the female accountant.

If you removed the articles, it would sound more generic or less natural in this context.

Because the subject is plural: ο λογιστής και η λογίστρια = two people.

• συμφωνεί = he/she/it agrees
• συμφωνούν = they agree

Since two people are doing the agreeing, Greek uses the 3rd person plural form.

Here συμφωνούν means they agree in the sense of sharing the same opinion or judgment.

So:

• συμφωνούν ότι... = they agree that...

It does not mean only making a formal agreement. It can simply mean that both people think the same thing.

ότι means that and introduces a clause:

• συμφωνούν ότι το τιμολόγιο είναι σωστό = they agree that the invoice is correct

This is different from ό,τι with a comma, which means whatever or anything that.

So:

• ότι = that
• ό,τι = whatever / anything that

That distinction is very important in writing.

Yes. τιμολόγιο is a neuter noun, so it takes the neuter article το.

Greek nouns belong to grammatical genders:

• masculine
• feminine
• neuter

So here:

• το τιμολόγιο = the invoice

The gender is grammatical, not based on real-world sex.

Because adjectives in Greek agree with the noun they describe in gender, number, and case.

Since τιμολόγιο is neuter singular, the adjective must also be neuter singular:

• το τιμολόγιο είναι σωστό

Compare:

• ο λογαριασμός είναι σωστός = masculine
• η απάντηση είναι σωστή = feminine
• το τιμολόγιο είναι σωστό = neuter

Because είναι belongs to a new clause with a different subject.

Main clause:

• Ο λογιστής και η λογίστρια συμφωνούν...

Inside the ότι clause, the subject changes:

• ότι το τιμολόγιο είναι σωστό

So είναι goes with το τιμολόγιο, which is singular.

Also, in Modern Greek, είναι is used for both he/she/it is and they are, so context tells you which it is.

Not in this sentence. λείπω often means to be missing, to be absent, or to be lacking.

So:

• δεν λείπει τίποτα = nothing is missing

It does not mean that someone emotionally misses something. For that meaning, Greek usually uses other structures, such as μου λείπεις = I miss you, which works differently.

Yes, from an English point of view it looks like a double negative, but this is completely normal in Greek.

Greek uses negative concord, which means several negative-looking words can appear together in the same negative sentence.

So:

• δεν λείπει τίποτα = nothing is missing

This is standard Greek, not a mistake.

The same pattern happens with words like:

• κανείς = nobody
• πουθενά = nowhere

Because τίποτα is grammatically singular.

So Greek treats it like a singular subject:

• τίποτα λείπει would be ungrammatical in this context
• δεν λείπει τίποτα is correct

This is similar to English nothing is missing, not nothing are missing.

Not always. Its meaning depends on the type of sentence.

• In negative sentences, τίποτα usually means nothing
• In questions or some other contexts, it can mean anything

Examples:

• Δεν βλέπω τίποτα. = I see nothing
• Βλέπεις τίποτα; = Do you see anything?

So in this sentence, because of δεν, it means nothing.

Greek word order is more flexible than English word order.

The sentence as given is neutral and natural:

• Ο λογιστής και η λογίστρια συμφωνούν ότι...

But Greek could move things around for emphasis, for example:

• Συμφωνούν ο λογιστής και η λογίστρια ότι...

That said, the original order is a very normal learner-friendly pattern: subject + verb + clause.

A rough pronunciation guide:

• Ο λογιστής = o lo-yee-STEES
• και η λογίστρια = ke ee lo-YEE-stria
• συμφωνούν = seem-fo-NOON
• ότι = O-ti
• το τιμολόγιο = to tee-mo-LO-yee-o
• είναι = EE-ne
• σωστό = so-STO
• δεν λείπει τίποτα = then LEE-pee TEE-po-ta

A few useful notes:

• The accent mark shows the stressed syllable.
• γι / γιο often sounds like yee / yo
• δ sounds like th in this
• αι in είναι sounds like e, so είναι is roughly EE-ne

Sometimes in everyday speech Greek can omit ότι, especially in informal contexts, but with a sentence like this, keeping ότι is very standard and clear.

So:

• συμφωνούν ότι το τιμολόγιο είναι σωστό...

is the safest and most natural form for learners.

It works just like English they agree that..., where that can sometimes be omitted, but is often kept for clarity.