Социальный вычет включает расходы на лечение.

Because вычет is a masculine noun, so the adjective must also be in the masculine form: социальный.

• masculine: социальный
• feminine: социальная
• neuter: социальное

So:

• социальный вычет = correct
• социальная вычет = incorrect
• социальное вычет = incorrect

This is basic adjective-noun agreement in Russian: the adjective must match the noun in gender, number, and case.

Включает is the 3rd person singular present tense form of включать.

That form is used because the subject is социальный вычет, which is:

• singular
• third person
• grammatically the thing doing the action

So:

• я включаю = I include
• ты включаешь = you include
• он / она / оно включает = he / she / it includes

Here, социальный вычет behaves like it, so Russian uses включает = includes.

Because включает is the imperfective verb, and it is the normal choice for stating a general fact or rule.

• включать → включает = to include / includes
• включить → включит = to include once / will include

In this sentence, the meaning is not about one future action. It is describing how the deduction works in general, so Russian prefers the imperfective:

• Социальный вычет включает... = The social deduction includes...

If you said включит, it would usually sound like will include.

Расходы is in the accusative plural because it is the direct object of the verb включает.

The verb включать takes a direct object:

• включать что? = include what?

Answer:

• расходы

For inanimate plural nouns, the accusative form is usually the same as the nominative form. So:

• nominative plural: расходы
• accusative plural: расходы

That is why the form does not change here.

In Russian, расходы на что is a very common pattern meaning expenses on / for something.

So:

• расходы на лечение = expenses for treatment
• расходы на обучение = expenses for education
• расходы на ремонт = expenses for repairs

After на in this pattern, Russian uses the accusative case.

So лечение here is accusative singular. But since лечение is a neuter noun, its nominative and accusative forms are the same:

• nominative: лечение
• accusative: лечение

Лечение is a neuter noun meaning treatment or medical treatment.

Its ending -ие is common for neuter nouns of this type. In this sentence it appears after на, in the accusative case, but the form stays the same.

Some forms:

• nominative: лечение
• genitive: лечения
• dative: лечению
• accusative: лечение
• instrumental: лечением
• prepositional: о лечении

A learner may also notice that it comes from the verb лечить = to treat / to heal.

Russian has no articles like English the and a/an.

So социальный вычет can mean:

• a social deduction
• the social deduction

and the exact interpretation depends on context.

Likewise:

• расходы на лечение can mean treatment expenses, expenses for treatment, or the expenses for treatment, depending on the situation.

Russian usually relies on context, word order, and emphasis instead of articles.

Yes, Russian word order is relatively flexible, but not all versions sound equally natural.

The neutral, standard order here is:

• Социальный вычет включает расходы на лечение.

This is the most natural way to present the sentence as a plain fact.

You could change the order for emphasis, for example:

• Расходы на лечение включает социальный вычет.

This is grammatically possible, but it sounds marked and would usually be used only if you especially want to emphasize расходы на лечение.

So for learners, the original order is the safest and most natural choice.

Good question. Расход / расходы can have different meanings depending on context.

Common meanings include:

• expense / expenses
• consumption / usage
• in some contexts, even outflow

In this sentence, because the phrase is расходы на лечение, the meaning is clearly expenses for treatment.

This is very common in financial, legal, and administrative language.

Yes, it sounds fairly formal and administrative. Words like:

• социальный вычет
• включает
• расходы на лечение

are typical of official, financial, or legal Russian.

In everyday speech, a person might explain the same idea in a more conversational way, but in official documents this kind of wording is very normal.

They would ask:

• Что включает социальный вычет? = What does the social deduction include?

And the answer would be:

• Расходы на лечение.

This is useful because it shows the case pattern of the verb:

• включать что? → accusative

So when you learn включать, it helps to memorize it together with its question pattern:

• включать что = to include what

The stress is:

• социАльный вы́чет включАет расхОды на лечЕние

A rough pronunciation guide for English speakers:

• социАльный → so-tsi-AL-nyy
• вы́чет → VYI-chet
• включАет → vklyu-CHA-yet
• расхОды → ras-KHO-dy
• лечЕние → li-CHE-ni-ye

A couple of pronunciation notes:

• включает begins with a consonant cluster, which can feel difficult at first.
• Unstressed о is often pronounced closer to a in normal speech.
• The stress matters a lot in Russian, so it is worth learning words together with their stressed syllables.