X+Y review – a charming mathematical uncertainty

X+Y is a likable fiction feature developed by director Morgan Matthews from his own award-winning 2007 documentary, Beautiful Young Minds, about young British mathematicians who are on the autism spectrum competing at the International Mathematical Olympiad: a “mathlete” event for superpowered maths brains. Asa Butterfield (the lead in Scorsese’s 2011 movie Hugo) plays Nathan, a teen maths star whose disorders are worsened by the death of his father, making him retreat into the comforting world of numbers.

His mother – an intelligent, compassionate performance from Sally Hawkins – must deal with it all as best she can. But then a troubled school maths teacher (Rafe Spall) enters Nathan for the maths Olympiad and there he finds his unemotional world rocked by an even more brilliant, beautiful maths whiz from China: Zhang Mei (Jo Yang). It’s an engaging film with a nice supporting performance from Eddie Marsan as the Olympians’ team coach, though the Olympiad itself turns out to be, somewhat oppressively, just one big, glorified exam, and the narrative question of whether some things are more important than maths is only really broached at the end of the film. But this is an attractively unparochial drama with a bracing interest in excellence.