Farina tam sicca est ut mater aquam addat.

Tam ... ut introduces a result clause in Latin.

• tam = so
• ut = that

So tam sicca est ut ... means is so dry that ...

This is a very common Latin pattern:

• tam
  • adjective/adverb + ut
• ita / sic
  • ut
• tantus / tot / talis
  • ut

In this sentence, tam strengthens sicca and sets up the result: the flour is so dry that the mother adds water.

Because it is inside a result clause, and Latin normally uses the subjunctive in result clauses after ut.

So:

• addit would be indicative: she adds
• addat is subjunctive: used here because the clause depends on tam ... ut

That is one of the first big uses of the subjunctive that learners meet: not because the action is unreal, but because Latin grammar requires the subjunctive in this kind of subordinate clause.

The main clue is tam.

A purpose clause usually answers why? and often has no word like tam in the main clause:

• mater aquam addit ut farina minus sicca sit
  = the mother adds water so that the flour may be less dry

A result clause shows what happens as a consequence, and it is often signaled by words such as:

• tam = so
• ita / sic = so, in such a way
• tantus = so great
• tot = so many
• talis = such

Here, Farina tam sicca est clearly sets up a consequence:

• the flour is so dry
• that the mother adds water

So this is a result clause, not a purpose clause.

Addat is:

• 3rd person singular
• present tense
• active voice
• subjunctive mood

It comes from addo, addere, addidi, additum, meaning to add.

So addat means something like:

• she may add
• or, in smoother English here, simply she adds

Because it is in a result clause, English often does not need to show the subjunctive very clearly in translation.

It is present because the main verb is also present: est.

Latin often follows a tense relationship called the sequence of tenses. With a present main verb, a result clause commonly uses the present subjunctive for action happening at the same time or as a natural consequence of the main clause.

So:

• est = is
• addat = adds / may add

If the main verb were past, the subordinate verb would often shift accordingly:

• Farina tam sicca erat ut mater aquam adderet
• the flour was so dry that the mother added water

Because it agrees with farina, which is a feminine singular noun.

Latin adjectives must agree with the nouns they describe in:

• gender
• number
• case

So:

• farina = feminine singular nominative
• sicca = feminine singular nominative

If the noun were masculine or neuter, the adjective would change too:

• masculine: siccus
• neuter: siccum

Here sicca simply matches farina.

They are:

• farina: nominative singular
  It is the subject of est.

• mater: nominative singular
  It is the subject of addat.

• aquam: accusative singular
  It is the direct object of addat.

So the structure is:

• Farina = the flour
• tam sicca est = is so dry
• ut mater aquam addat = that the mother adds water

Because it is the direct object of addat.

The verb addo takes an object: you add something. Here, the thing being added is water, so Latin puts aqua into the accusative:

• nominative: aqua = water
• accusative: aquam = water as the object

So mater aquam addat means the mother adds water.

Yes, Latin could leave it out if the subject were clear from the verb ending.

Since addat is 3rd person singular, it already tells us:

• he/she/it may add

So Latin could say:

• Farina tam sicca est ut aquam addat

That could still mean the flour is so dry that she adds water, depending on context.

But mater is included here to make the subject explicit:

• to show exactly who is adding the water
• or to add a bit of emphasis or clarity

Because the two clauses do different jobs.

The main clause:

• Farina tam sicca est
• states a fact or description
• so it uses the indicative

The subordinate clause:

• ut mater aquam addat
• is a result clause
• so it uses the subjunctive

This is very normal in Latin: the main clause can be indicative, while the subordinate clause has a special construction requiring the subjunctive.

Yes, this is perfectly normal Latin word order.

Latin word order is more flexible than English because the endings show the grammar. Still, some patterns are common:

• the main statement comes first
• the ut clause often follows
• the verb often comes late in its clause

So this sentence is arranged very naturally:

• Farina
• tam sicca est
• ut mater aquam addat

Latin often uses word order to highlight ideas. Here the sentence first presents the condition:

• the flour is so dry

Then it gives the consequence:

• that the mother adds water

Yes. Ut is a very flexible word in Latin. Depending on context, it can mean things like:

• that
• so that
• when
• as
• how

That is why context matters so much.

In this sentence, because of tam, the meaning is clearly the result-clause ut:

• so ... that

So here ut is best understood as that in the pattern so dry that.

Grammatically, addat is subjunctive, so a very literal gloss might be may add. But in natural English, that often sounds awkward.

In this sentence, the best English usually just says:

• the mother adds water

So it is useful to remember:

• subjunctive form in Latin
• but often ordinary English in translation

The important thing is not to force English may every time you see a Latin subjunctive. Here the subjunctive is mainly there because the clause is a result clause.