'Darts' is a noun, which 'looks' plural, but is used as 'singular'.
played by men as well as women.
To understand this type of errors, we must understand the behavior of nouns.
Nouns can be divided into several types, as covered in this and following questions.
|News, Mathematics, Ethics, Linguistics, Phonetics, Politics, Economics, Statistics, Measles, Rickets, Billiards, Darts, Droughts, Innings, Gymnastics, Mechanics, Classics, Physics, Summons, Gallows|
|Incorrect:||Mathematics are a difficult subject.|
|Correct:||Mathematics is a difficult subject.|
|Incorrect:||Politics are a dirty game.|
|Correct:||Politics is a dirty game.|