A mid-term music exam recently made rounds on Korean social networking sites. The fill-in-the-blanks section was asking for the number of members in the Korean-Chinese male group, Exo.

"A" who posted the test online reacted, "How am I supposed to know how many members are in EXO..."  

The student also claimed that he did not pass the test because of the question, AllKpop reports.

Netizens, even Kpop fans, agree that the question was tricky.

Despite its quick rise to fame and overwhelming popularity across South Korea, China, and many Asian countries, Exo isn't perfect - the SM Entertainment group keeps on losing its members.

Debuting in 2012 with a dozen boys, the group who sang megahits "Wolf" and "Growl" are down to nine members in three years following the one-by-one departure of Chinese members Kris, Luhan and Tao.

With chart topper's frequent line-up changes, it's unsurprising that even Kpop fans are unsure of the group's current population.

A netizen reacts, "It's flustering that a music test would ask for the number of members, but what does that even have to do with idol group's music?" 

Others are suggesting the question was intended as a bonus.