"This table is low."

Translation: このテーブルは低いです。

[Falcon198016]

このテーブルは低いです。

[TyrantRC]

低い【ひくい】

[PeaceAndWar208]

I wish Duolingo introduced the Kanji before giving us the reading so that I wouldn't have to look them all up myself -_-

[Nancy676366]

I accidentally clicked on next before adding です at the end and it was right??

[KagayakuSeiza]

Yes, that's still a grammatically correct answer. Since ひくい is an い adjective, the です is only needed in formal speech. In informal speech, sentences ending in an い adjective omit the です, whereas if it was a な adjective (like きれい for example), the です would be replaced with だ.

[Ri-nee-chan]

In which context does one use "机"? Where is　"テーブル" preferable?

[V2Blast]

机（つくえ) means "desk", which is different from a table.

[MHKuntug]

Sounds like "Shikui" instead of "Hikui" in the lesson.

[bookrurouni]

このテーブルは低いだ　ってだめですか。

[V2Blast]

Yes, that would be incorrect. As @KagayakuSeiza's comment points out above, when the sentence ends in an い-adjective (e.g. ひくい、あつい), the informal form simply loses the です. With a な-adjective (e.g. きれい、しずか), the informal form changes です to だ.

[Tobidesu]

Couldn't it be この卓は低いです ???