Mater sudorem e fronte pueri tergit.

Because mater is in the nominative singular, which is the case normally used for the subject.

Not all Latin nominatives look alike. Mater is a third-declension noun, so its nominative singular form is simply mater. You learn it as a whole word, not by spotting a standard subject ending.

So in this sentence:

• mater = the mother → subject
• tergit = wipes

Together: The mother wipes ...

Because sudorem is the direct object of tergit, so it is in the accusative singular.

The basic dictionary form is sudor = sweat.
Its accusative singular is sudorem.

So:

• sudor = sweat
• sudorem = sweat, as the thing being wiped

In the sentence, the mother is wiping the sweat, so Latin puts sudor into the accusative: sudorem.

E means from or out of. After e (or ex), Latin uses the ablative case.

The noun is:

• frons = forehead, brow
• fronte = from the forehead / on the forehead / by the forehead, depending on context

Here, because of e, it means:

• e fronte = from the forehead

So fronte is ablative singular because the preposition e requires the ablative.

Because pueri here is genitive singular, meaning of the boy.

The phrase e fronte pueri means:

• from the forehead of the boy
• more naturally in English: from the boy’s forehead

If it were puerum, that would be accusative singular, which would suggest that the boy was a direct object. But the boy is not what is being wiped; sweat is what is being wiped.

So:

• pueri = of the boy
• puerum = the boy as a direct object

Because pueri can indeed mean more than one thing depending on context:

• genitive singular = of the boy
• nominative plural = the boys

Here, context makes the meaning clear. In e fronte pueri, the word pueri is attached to fronte and tells whose forehead it is. So it must mean of the boy, not the boys.

A nominative plural pueri would usually act as a subject, but the subject here is already clearly mater.

Because Latin does not have definite and indefinite articles like English the and a/an.

So Latin often just uses the noun by itself:

• mater can mean mother or the mother
• pueri can mean of a boy or of the boy
• sudorem can mean sweat or the sweat

You decide from context what sounds natural in English.

Because Latin word order is much more flexible than English word order. Very often, especially in simple narrative or textbook Latin, the verb comes at or near the end.

So:

• Mater sudorem e fronte pueri tergit
• literally: Mother sweat from forehead of-the-boy wipes

In natural English, we rearrange it:

• The mother wipes sweat from the boy’s forehead.

Latin uses endings more than position to show how words function, so moving the verb to the end does not create confusion.

Tergit is:

• third person singular
• present tense
• active voice
• indicative mood

So it means:

• he wipes
• she wipes
• it wipes

Because the subject is mater, it means she wipes or the mother wipes.

The verb comes from tergo, tergere, meaning to wipe.

Yes. E and ex both mean from or out of.

A common guideline is:

• ex before vowels or h
• e often before consonants

Since fronte begins with f, e fronte is perfectly normal.

So e fronte pueri is exactly what you would expect here.

Latin often uses the genitive to show possession, especially when English would use 's.

So:

• frons pueri = the boy’s forehead
• e fronte pueri = from the boy’s forehead

A possessive adjective like suus is used when Latin wants to say his own, her own, their own, and it refers back to the subject of the clause. But here the subject is mater, not the boy. So suus would naturally refer to the mother’s own forehead, which would be wrong.

That is why pueri is the right choice.

Yes. Latin often expresses this idea as:

• direct object = the thing removed
• e/ex
  • ablative = the place it is removed from

So the structure is:

• sudorem = the sweat
• e fronte pueri = from the boy’s forehead

This is a very normal and clear Latin pattern: remove/wipe X from Y.

Here is the breakdown:

• mater — nominative singular
  the mother → subject

• sudorem — accusative singular
  sweat → direct object

• fronte — ablative singular
  from the forehead → object of e

• pueri — genitive singular
  of the boy → shows possession

This is a good example of how Latin endings show each word’s job in the sentence.