Aquest exercici és fàcil.

Aquest means this.

It is the masculine singular demonstrative, used for a noun that is masculine and singular, like exercici.

So:

• aquest exercici = this exercise

Related forms are:

• aquest = this (masculine singular)
• aquesta = this (feminine singular)
• aquests = these (masculine plural)
• aquestes = these (feminine plural)

Because exercici is a masculine singular noun.

In Catalan, words like this must agree with the noun they go with. So:

• aquest exercici = this exercise
• aquesta activitat = this activity

English does not change this, but Catalan does.

Exercici is masculine.

Often, you learn the gender together with the noun. A useful clue is that many Catalan nouns ending in -i are masculine, though this is not a perfect rule.

You can also tell from the sentence because it uses:

• aquest instead of aquesta

If you add the article, it would be:

• l’exercici = the exercise

That also shows it is masculine.

Because aquest already means this, so you do not also add the.

In English, we say this exercise, not this the exercise. Catalan works the same way:

• aquest exercici = this exercise

Not:

• el aquest exercici

So demonstratives like aquest/aquesta normally replace the article.

És is the third-person singular form of the verb ser, meaning to be.

So:

• és = is

In this sentence:

• Aquest exercici és fàcil = This exercise is easy

Some common forms of ser are:

• sóc = I am
• ets = you are
• és = he/she/it is
• som = we are
• sou = you all are
• són = they are

The accent in és helps distinguish it from es, which is a different word.

• és = is
• es = a reflexive/pronominal word, often like oneself, himself, herself, etc.

The accent also shows the stressed vowel.

So the accent is important both for meaning and pronunciation.

The accent in fàcil shows where the stress falls:

• FÀ-cil

Without the accent, the word would not follow normal stress expectations.

In Catalan, written accents often help you know how to pronounce a word correctly. Here, fàcil means easy and is stressed on the first syllable.

In the singular, fàcil is the same for both masculine and feminine.

So you can say:

• Aquest exercici és fàcil = This exercise is easy
• Aquesta activitat és fàcil = This activity is easy

In the plural, it becomes:

• fàcils

For example:

• Aquests exercicis són fàcils = These exercises are easy
• Aquestes activitats són fàcils = These activities are easy

So it changes for number, but not for gender in the singular.

Yes. The basic word order here is very similar to English:

• Aquest exercici = subject
• és = verb
• fàcil = adjective/complement

So it matches:

• This exercise is easy

Catalan often uses this same straightforward order in simple statements.

A simple English-friendly approximation is:

• ah-KEST ehk-sehr-SEE-see ez FAH-seel

A few notes:

• aquest ends with a clear t
• exercici has stress on the -ci- near the end
• és sounds like ez or ace without the a glide, depending on accent
• fàcil is stressed on the first syllable: FAH-cil

Pronunciation varies somewhat by dialect, but that approximation is good for a learner.

You need to change the demonstrative, the noun, the verb, and the adjective:

• Aquest exercici és fàcil = This exercise is easy
• Aquests exercicis són fàcils = These exercises are easy

Changes:

• aquest → aquests
• exercici → exercicis
• és → són
• fàcil → fàcils

This is a good example of agreement in Catalan.

Normally, no. In standard Catalan, for a basic description like easy, you usually use ser, not estar:

• Aquest exercici és fàcil

Catalan, like Spanish, often distinguishes between ser and estar, but with inherent or general descriptions such as easy, difficult, important, interesting, ser is the normal choice.

So és fàcil is the natural form here.

To make it a question, you can usually just use intonation, and in writing you add a question mark:

• Aquest exercici és fàcil? = Is this exercise easy?

To make it negative, add no before the verb:

• Aquest exercici no és fàcil. = This exercise is not easy.

That is a very common pattern in Catalan:

• no + verb

For example:

• Aquesta activitat no és difícil. = This activity is not difficult.