A Disappearing Number, Barbican, London

In one of her movies, there's a scene that finds Mae West in unfamiliar pedaogogic mode. She stands before a blackboard and addresses a classroom of children: "Listen, kids," she drawls, "there are only three things you need to know in life. One and one make two. Two and two make four. And four and four make 10 – if you know how to work it right."

I thought of Mae, and her inventive calculations, several times while watching A Disappearing Number, the latest brilliant show by Complicite. The piece is conceived and directed by Simon McBurney who is easily, to my mind, the greatest creator of theatre in this country.

Mae may have heard of the World Series, but I doubt that she knew anything about the Infinite Series, and I wondered how she would have coped at this show which pulls together ideas about mathematics, music, mysticism, mortality, and about motherhood as a mode of creativity to rival imaginative work at the outer reaches of mathematical thought.

The result, as is the case with all McBurney's mature theatre pieces, is both mind-bending and heart-stopping. His earlier, award-winning show, Mnemonic, investigated the concept of memory and tied this in with a meditation on our connectedness to the past and to place.

A Disappearing Number sets itself a harder task. Thoughts about memory strike an instinctive chord with everyone, whereas many people have just as knee-jerk a resistance to maths. What this show, which is more uneven than Mnemonic, manages triumphantly (at its best) is to create an almost umbilical link between the cerebral and the visceral.

Like its predecessor, A Disappearing Number intertwines ostensibly separate narratives and spans continents, producing a dazzling network of emotionally charged connections. At its centre is the remarkable, real-life story of the historic mathematical collaboration of GH Hardy, a brilliant don at Trinity College, Cambridge and the self-tutored Brahmin genius, Srinivasa Ramanujan who came to England, at Hardy's request, worked with him at the time of the First World War and died in India in his early thirties.

The tale of this pair is counter-pointed by the travails of a fictional couple: Al, an American-Asian futures dealer and his partner, Ruth, an English mathematician who is haunted by the ticking of the biological clock and the short shelf-life of a maths boffin's talent.

The stage-craft is of breathtaking beauty. Equations swarm like a algebraic shower of snow over the severe grey set. A blackboard rotates to become a screen with rushing images of India. The groupings of actors highlight with a diagrammatic force the deep resemblances and difference between the two situations. The progressions from one to the other are magically fluid – at one point, for example, Ramanujan, a vegetarian short of sustenance in First World War Cambridge, picks up an apple from the abundant "hospitality" bowl in the anonymous modern airport hotel room occupied by the futures dealer. Nitin Sawhney's score, with its hypnotic chanting, demonstrates that music is mathematics made audible.

A Disappearing Number is pellucid, puckishly funny and terribly poignant, as the contingent world of pain is contrasted with the self-sufficient aesthetic beauty of the mathematical realm. The fathomlessly intriguing concept of the infinitely divergent series (which move closer and closer, without ever becoming two) is made harrowing flesh in the failure of the modern couple to have a child and become three.

Hardy's belief that real maths has, by definition, to be useless, is complicated by an evocation of the First World War in Cambridge that suggests that the results of applied maths are far from morally neutral.

I sometimes felt that the contemporary couple got in the way of a better appreciation of Ramanujan and Hardy and heard a slight creak of contrivance in their narrative. But to the sum of great Complicite shows, A Disappearing Number is a noble addition.

To 6 October (020-7638 8891)