Information: - Mathematics (from Greek "mathma", knowledge, study, learning) is the study of topics such as quantity (numbers), structure, space, and change. There is a range of views among mathematicians and philosophers as to the exact scope and definition of mathematics. - John Edensor Littlewood (9 June 1885 6 September 1977) was a British mathematician, best known for his achievements in analysis, number theory, and differential equations and for his long collaboration with G. H. Hardy. - Godfrey Harold "G. H." Hardy FRS (7 February 1877 1 December 1947) was an English mathematician, known for his achievements in number theory and mathematical analysis. - A mathematical problem is a problem that is amenable to being represented, analyzed, and possibly solved, with the methods of mathematics. This can be a real-world problem, such as computing the orbits of the planets in the solar system, or a problem of a more abstract nature, such as Hilbert's problems.<br> It can also be a problem referring to the nature of mathematics itself, such as Russell's Paradox. - A mathematician is someone who uses an extensive knowledge of mathematics in his/her work, typically to solve mathematical problems. - Stanley Skewes ( 1899 -- 1988 ) was a South African mathematician , best known for his discovery of Skewes number in 1933 . He was one of John Edensor Littlewood 's students at Cambridge University . After reading the paragraphs above, we are interested in knowing the entity with which 'stanley skewes' exhibits the relationship of 'field of work'. Find the answer from the choices below. Choices: - collaboration - english - mathematician - mathematics - nature - number theory
A:
number theory