Magistra discipulam monet ut responsum in charta clare scribat.

It has two parts:

• Magistra discipulam monet = the main clause
• ut responsum in charta clare scribat = a subordinate clause introduced by ut

So the sentence works like this: the teacher warns/advises the student that she should write the answer clearly on the paper.

Latin does not have articles like English the and a/an.
So magistra can mean the teacher or a teacher, discipulam can mean the student or a student, and so on.

You decide from context which English article sounds right.

Because discipulam is accusative singular. It is the direct object of monet.

• discipula = nominative singular, the student as subject
• discipulam = accusative singular, the student as object

So in this sentence, the teacher is doing the warning/advising, and the student is receiving it.

Monet comes from moneo, monere. Depending on context, it can mean:

• warns
• advises
• reminds

In this sentence, advises or warns fits best.
It does not mean simple physical showing; it means giving guidance or warning to someone.

Here ut introduces an indirect command.

After verbs such as monet meaning warns/advises, Latin often uses:

• ut
  • subjunctive = a positive command or instruction
• ne
  • subjunctive = a negative command or instruction

So ut ... scribat means something like to write or that she should write in English.

Because it is inside an ut clause of indirect command.

After monet, Latin normally does not use a plain indicative here. It uses the subjunctive:

• monet ut scribat = advises/warns her to write

Also, the main verb monet is present tense, so the present subjunctive scribat is the normal choice here.

The understood subject is discipulam, the student.

English says The teacher advises the student to write...
Latin says The teacher advises the student that she should write...

Latin often leaves the subject of the subordinate verb unstated when it is clear from context. So scribat is understood as the student writes / should write, not the teacher.

Here it is a noun, meaning answer or response.

It is accusative singular and is the direct object of scribat:

• scribat quid? = what should she write?
• responsum = the answer

A learner may notice that responsum can look like a verbal form, but in this sentence it is simply the noun responsum, responsi, a neuter second-declension noun.

Because responsum is a neuter second-declension noun.

For many neuter second-declension nouns:

• nominative singular ends in -um
• accusative singular also ends in -um

So responsum can be either nominative singular or accusative singular in form.
Here it must be accusative singular because it is the object of scribat.

Because in takes different cases depending on meaning:

• in
  • ablative = location, in/on
• in
  • accusative = motion into/onto

Here the idea is location: the answer is written on the paper or on the sheet, not moved into it. So Latin uses the ablative:

• in charta = on the paper / on the sheet

Because clare is an adverb, and it modifies the verb scribat.

It tells us how the student should write:

• clare scribat = she should write clearly

Compare:

• clare = clearly, an adverb
• clarum responsum = a clear answer, where clarum is an adjective describing responsum

So Latin is not saying a clear answer here; it is saying the answer should be written clearly.

Latin word order is much more flexible than English word order because the endings show the grammatical roles.

This order is perfectly natural:

• Magistra discipulam monet ut responsum in charta clare scribat

But Latin could also rearrange parts without changing the basic meaning, for example:

• Magistra monet discipulam ut clare responsum in charta scribat

The original order puts magistra first, then discipulam, then the instruction. Also, placing scribat at the end of the subordinate clause is very common in Latin.