Hectopascal - Vol. 1 Ch. 23

[MangaDex]

 

[Speed509]

HOW THE HELL ARE THEY 19 AND 18, the 19 year old looks like he's in his 40's!!!

 

[JustALolicon69]

NO FKIN WAY THOSE MOFOS ARE 18 AND 19!!!! I WANNA LOOK MANLY LIKE THOSE GUYS!!!

 

[TheAmberFang]

HOW THE HELL ARE THEY 19 AND 18, the 19 year old looks like he's in his 40's!!!

NO FKIN WAY THOSE MOFOS ARE 18 AND 19!!!! I WANNA LOOK MANLY LIKE THOSE GUYS!!!

Pretty sure the numbers are their group ranks, meaning they are the 18th and 19th rank. It's also been used for the other groups, though it was for the top 8 in the high school and mostly just the top 2 with the Incheon gang.

Edit: Or maybe not. They were literally called "brats" in the next chapter, so I guess the numbers really are supposed to be their ages lol