It’s the little things that make characters feel real in James Graham’s X+Y script, which portrays autistic hero Luke as a person, rather than a pick-n-mix of “disabled genius” clichés. As the math-obsessed, socially awkward teen, who confesses to seeing the world “differently”, Asa Butterfield is superb. Following the death of his dad, Luke is inspired by his MS-suffering math tutor, (a suitably cynical Rafe Spall), to compete in the International Mathematical Olympiad (an Olympics for math – who knew?). As Luke’s long-suffering mum, Sally Hawkins conveys subtle grace as he rejects her touch, or demands his Chinese take-away contain a prime number of prawn balls.
Morbid sentimentality is avoided, thanks to liberal helpings of hope and humour, provided largely by Spall, whose wry wit acts as a defence against his debilitating disease. Hope lies in the possibility that Luke’s lonely mother and tutor have a shot at happiness, as do Luke and the Chinese prodigy he meets at a Taiwanese math training camp. Thrown in with numbers nerds, Luke is just another geek. As Nathan, a fellow autistic competitor, warns: “It’s alright being weird, as long as you’re gifted. But if you’re not gifted, all that leaves is weird.”
As the narrative heads to the Math Olympic finals, director Morgan Matthews avoids Hollywood highs in favour of down-to-earth domesticity. It’s brave to be so simple, and rewarding to see such subtlety. As Luke’s mum tells him: “I like you – more than ice-cream.” I liked X+Y. As much as any ice-cream. It’s refreshing, delightful stimulation for heart and mind.