His major contribution was the
Jigu suanjing ("Continuation of Ancient Mathematics" 缉古算经), written before year 626. Jigu Suanjing became a text for the
imperial examinations; it was included as one of the
Ten Computational Canons when reprinted in 1084. The book contains 20 problems based mostly on engineering construction of astronomic observation tower, dike, excavation of a canal bed etc. and
right angled triangles, but which in essence deal with the solution of
cubic equations, the first known Chinese work to deal with them. In Jigu Suanjin, Wang established and solved 25 cubic equations of the form: x^3+px^2+qx=N, along with 2
quadratic equations and 2 double
quadratic equations. Wang's work influence later Chinese mathematicians, but it is said that it was his ideas on
cubic equations which influenced the Italian mathematician
Fibonacci after transmission via the
Islamic world. ==Sources==