Learn Hardcore Romanian: Acest exemplu este mai ușor decât exercițiul din ziar. - This example is easier than the exercise from the newspaper.

Acest is a demonstrative adjective that stands directly before a masculine / neuter singular noun: acest exemplu = this example.
Acesta is the corresponding pronoun; it usually replaces the noun and stands on its own: Acesta este mai ușor = This (one) is easier.
Această is the feminine form used before a feminine singular noun: această problemă = this problem.
So in this sentence you must use acest because it comes before exemplu and describes it.

Why does exercițiul have -ul at the end?

In Romanian, the definite article (the) is usually attached to the end of the noun.

exercițiu = an exercise (indefinite)
exercițiul = the exercise (definite)

So exercițiul din ziar literally means the exercise from the newspaper. The -ul ending is just the masculine / neuter singular definite article.

Why is it din ziar and not something like ziarul or în ziar?

Din literally means from, but with publications it very often corresponds to English in as well: exercițiul din ziar ≈ the exercise in the newspaper.
If you say din ziarul…, then you’re specifying a particular newspaper:

exercițiul din ziar = the exercise in a newspaper / in the newspaper (not very specific)
exercițiul din ziarul de azi = the exercise in today’s newspaper

În ziar is used more for “in the newspaper” as a location of information: În ziar scrie că… (In the newspaper it says that…). For something that comes from or is taken out of the paper (like an exercise), din ziar is more natural.

How does the comparative mai ușor decât work? Is mai always needed?

For most adjectives, Romanian forms the comparative with mai + adjective:

ușor = easy
mai ușor = easier / more easy

You can’t drop mai here; ușor alone just means easy, not easier.
The usual pattern is: mai + adjective + decât to say more … than:
mai interesant decât, mai mare decât, mai important decât, etc.

When do I use decât instead of ca or cât?

For a comparison of inequality (more/less than), standard Romanian uses decât:

mai ușor decât exercițiul din ziar = easier than the exercise in the newspaper

For equality (as … as), you use la fel de / tot atât de … ca / cât:

la fel de ușor ca exercițiul din ziar = as easy as the exercise in the newspaper

You may hear people say mai ușor ca… in speech, but in careful / standard language, after mai / mai puțin, you should use decât.

What gender are exemplu and exercițiul, and how does that affect the other words?

Both exemplu and exercițiu are neuter nouns. In Romanian, neuter nouns behave like masculine in the singular and like feminine in the plural.

singular: un exemplu, exemplul, acest exemplu, mai ușor
singular: un exercițiu, exercițiul, acest exercițiu, mai ușor

Because they are masculine-like in the singular, you use masculine forms with them here: acest and ușor (not această, ușoară, etc.).

How would this sentence look in the plural (these examples are easier than the exercises in the newspaper)?

One natural plural version is:
Aceste exemple sunt mai ușoare decât exercițiile din ziar.

Changes to notice:

acest exemplu → aceste exemple (neuter plural uses aceste)
este → sunt (is → are)
ușor → ușoare (neuter plural takes the feminine plural adjective form)
exercițiul → exercițiile (the exercise → the exercises)

Is the word order fixed, or can I move parts of the sentence around?

The given word order is the most neutral:
Acest exemplu este mai ușor decât exercițiul din ziar.

You can change the order for emphasis, for example:

Exemplul acesta este mai ușor decât exercițiul din ziar.
Este mai ușor acest exemplu decât exercițiul din ziar. (emphasis on easier)

All of these are grammatically correct; changing the order mainly affects what sounds more emphatic or more colloquial.

How do I pronounce the words in this sentence, and what about the special Romanian letters?

Approximate pronunciations for an English speaker:

acest ≈ a-CHESST (like ch in church
- e in get)
exemplu ≈ eg-ZEM-plu
este ≈ YES-teh (in speech you often hear just e, pronounced like eh)
mai ≈ my
ușor ≈ oo-SHOR (ș = sh in shoe)
decât ≈ de-KÂT (â is a central vowel, a bit like a tight uh)
exercițiul ≈ eg-zer-CHEE-tsyul (ț = ts in cats)
ziar ≈ zee-AR

The letters ș and ț must be written with the comma/cedilla; writing s and t instead (usor, exercitiul, decat) is common online but considered incorrect spelling.

What’s the difference between exemplu and exercițiu?

Exemplu means example – something used to illustrate a rule, idea, or pattern.
Exercițiu means exercise – a task you are supposed to do (solve, fill in, transform a sentence, etc.).
So the sentence is contrasting a sample/example with a practice task: the example is easier than the exercise from the newspaper.

In everyday speech, you might also hear more colloquial versions like:

Exemplul ăsta e mai ușor decât ăla din ziar. (This example is easier than that one from the newspaper.)
Here ăsta / ăla are informal versions of acesta / acela, and e is the short spoken form of este.