Merces in tres pensiones dividitur.

Because merces is a third-declension noun. In the third declension, some nouns have a nominative singular ending in -es.

So here:

• merces = nominative singular
• it is the subject of the sentence

Even though -es often looks plural to an English speaker, in this word it is singular.

The subject is merces.

You can tell because:

• dividitur means is divided
• the thing that is divided must be the subject
• merces is in the nominative case, which is the usual case for the subject

So the sentence is literally structured as:

• Merces = the payment / price / fee
• in tres pensiones = into three installments
• dividitur = is divided

Because dividitur is the present passive form of dividere.

Breakdown:

• dividere = to divide
• dividit = he/she/it divides
• dividitur = he/she/it is divided

The ending -tur is a very common sign of the passive voice in Latin.

So dividitur means:

• is divided
• or sometimes is being divided, depending on context

The verb is singular because the subject, merces, is singular.

Latin verbs agree with their subject in number:

• singular subject → singular verb
• plural subject → plural verb

Since merces is singular, Latin uses dividitur, not a plural form like dividuntur.

Here in means into.

Latin uses in + accusative when there is movement into something, or a change into a new state or division.

So:

• in tres pensiones = into three installments

This is different from in + ablative, which usually means in / on in the sense of location.

For example:

• in urbe = in the city
• in urbem = into the city

In this sentence, the payment is being divided into parts, so the accusative is used.

Tres pensiones is accusative plural.

Why?

Because it follows in in the sense of into, and that requires the accusative.

So:

• tres = three
• pensiones = installments / payments
• together: into three installments

This phrase shows the result of the division.

Because pensiones is feminine plural, and tres is the form used for masculine and feminine nouns.

Latin three works like this:

• tres = masculine or feminine
• tria = neuter

Since pensio is feminine, Latin says:

• tres pensiones

not

• tria pensiones

Here pensiones means installments or payments.

So the sentence means that the total merces is divided into three separate payments.

A learner should note that the best English translation depends on context:

• installments
• payments
• sometimes payment periods

But in this sentence, installments is usually the most natural choice.

Merces can have several meanings in Latin, including:

• wages
• pay
• fee
• price
• reward

In this sentence, it most naturally means something like:

• the payment
• the fee
• the amount owed

Since you already know the overall meaning, the important point is that merces is the amount that gets divided into installments.

Because Latin word order is flexible, and it is very common for the verb to come last.

So:

• Merces in tres pensiones dividitur

is a normal Latin order.

Latin uses endings more than word order to show grammar, so the sentence could be rearranged without changing the basic meaning. For example:

• In tres pensiones merces dividitur

would still mean the same thing.

The original order is simply a natural Latin way to present the sentence.

Yes.

The Latin present passive can often be translated either as:

• is divided
• is being divided

Which one sounds better depends on context.

So this sentence could suggest either:

• a general arrangement: the payment is divided into three installments
• an action happening now: the payment is being divided into three installments

In many textbook sentences, English prefers the simpler is divided.

No. Latin has no articles.

So merces could be understood as:

• the payment
• a payment

and tres pensiones as:

• three installments

English must choose an article when translating, but Latin does not express that directly.

In most contexts here, English would naturally say:

• The payment is divided into three installments.

Yes, roughly like this:

• Merces = payment / fee
• in = into
• tres = three
• pensiones = installments
• dividitur = is divided

So the literal order is:

The payment into three installments is divided.

That is understandable, but not natural English. Better English is:

The payment is divided into three installments.