Many school subjects are plurals, like physics, economics, and forensics. More to the point: mathematics. So, while it’s gratuitous pluralization, it’s not completely out of left field. To Americans, hearing a Commonwealthian says “maths” sounds cute. The other way around, I think it sounds more directly incorrect, like somebody saying they studying “particle physic” or “home economic”.
At least for the American accent, “maths” is not just a needless plural, but a homonym with “mass”. So if it caught on, it could be included on this game show.
Jeremy’s winner: math (close one, but not enough of an edge to justify the extra phoneme)