"Dieser Tisch ist größer."

Translation: This table is bigger.

[horts42]

why not larger

[mizinamo]

That's a reasonable translation, just one that the Pearson team ( https://www.duolingo.com/comment/24066422 ) didn't think of when they added this sentence. Report it as "my translation should be accepted" the next time you come across this sentence.

[Michael843717]

One week later, "larger" is still marked as incorrect. FYI

[mizinamo]

I don't know whether the Pearson team looks at reports for their own sentences at all, nor how many people they have and how much time they have for reviewing sentences.

On the public course, a week is much too short to expect a response, I'm afraid, given the number of volunteer contributors and the free time they have each week versus the number of sentences in the course.

[extnull]

Why do we use dieser?

[terminalmage]

Tisch is masculine and the case is nominative, so dies ist declined using -er.

[JCe9fi]

What is the difference between dies and mein? We wouldn't say meiner Tisch, right?

[mizinamo]

Correct. mein is like ein and kein and has no ending for masculine or neuter nominative if they are before a noun.

dies-, on the other hand, does: dieser Mann, diese Frau, dieses Kind versus ein Mann, eine Frau, ein Kind.

[JCe9fi]

Soooo, I get the feeling that dies behaves like an adjective. Is it considered one?

[mizinamo]

I'd call it a "demonstrative determiner".

And it doesn't behave quite like an adjective -- the endings are like the definite article, e.g. -s in masculine/neuter genitive, while strong adjectives have -n: der Preis guten Weines versus der Preis dieses Weines and der Preis des Weines "The price of good wine / of this wine / of the wine".