The main cause of Nathan’s lack of interconnections with people is due to his loss of his father with whom he had the closest relationship that he could ever have. His father had been killed in a car accident next to little Nathan who would not forget that moment until the end of his life. After his trauma, he simply closes himself to any potential human connections, even with his loving mother. Although his mother doesn’t seem to mind it and still endeavors to reach her child, her pain is conspicuous behind her forced smiles and worried eyes. When she comes to realize that her son finds comfort in numbers rather than anything and is exceptionally good at math, she decides to enroll him in advanced math classes at a new school.

 

There, Nathan meets his private math teacher who also is a genius and once contested in the International Mathematics Olympiad (IMO) but had to give up all when he was diagnosed with his illness. They start to study together to further Nathan’s math skills. He grows up over the course of the movie and comes to an age at which he could take exams to prove his ability. He fears that he is not good enough to qualify, but he ends up doing well in the exam. After his success, he gets recognized and is invited to the two-week math camp that is going to take place in Taiwan.

 

Nathan accompanies 15 other British students as they arrive in Taiwan. They get united with China's team to prepare for the qualifying exam to contest in IMO. Nathan gets to meet a Chinese female student, Zhang Mei, as he is paired with her to go through the entire marathon. Unlike the other students, they start to spend a good amount of time together. Zhang Mei takes Nathan out to introduce Taiwan as they slowly develop trust in each other. She helps him adjust to his new surroundings and fight his fears when the exam is near. By the skin of their teeth, they win their place at their own national team to compete in the IMO.

 

This year the prestigious competition is going to be held in Cambridge, England. After they travel back to England, Zhang is arranged to stay with Nathan and his mother. Nathan’s mother is surprised by Nathan’s newly transformed behavior which is more normal than before. She becomes aware that he may have feelings for Zhang from Nathan’s certain attitude. When she asks him Nathan doesn’t give a decent response as he is far from familiar with the concept of “love.” Without knowing how to express them, he keeps all his emotions to himself as they travel to Cambridge for the Olympiad the next day.

 

The morning of the exam, when Zhang’s uncle catches her in Nathan’s room thinking she is “distracting” herself, they get into a fight. Zhang can’t bear all the pressure regardless of her efforts and decides to withdraw from the Olympiad. She says goodbye to Nathan and leaves. Nathan is now clueless of what he is supposed to do or feel but finally is sure that he loves Zhang. He is torn between her and the Olympiad. He gets ready for the contest and takes his seat among hundreds of students around the world in a huge saloon in the Cambridge University that is surveilled by many people and each national teams’ teacher. As the exam begins, he reads the first question, and it somehow triggers his childhood memories of his dead father to a degree that he can’t keep his mind off. Combined with his newly lost love, an emotional overload haunts Nathan. He stands up instantly and looks for the exit door. He takes slow steps to the door as his teacher is trying to understand what’s going on. He then rushes out of the exam hall and the university of Cambridge. Later, his mother finds him in a café nearby, where he confides in herself for the first time in his life. He speaks about his emotional overload which the loss of his father and the girl who appreciated and loved him created. They embrace at last and decide to go after Zhang Mei. His mother drives Nathan to the station to fetch Zhang Mei after Nathan leaves everything behind, including his childhood dream.

 

References

“X+Y”, Wikipedia, https://en.wikipedia.org/wiki/X%2BY

Imdb.com https://www.imdb.com/title/tt3149038/