Abstract
An m-point nonlocal boundary value problem is posed for quasi-linear differential equations of first order on the plane. Nonlocal boundary value problems are investigated using the algorithm of reducing nonlocal boundary value problems to a sequence of Riemann-Hilbert problems for a generalized analytic function. The conditions for the existence and uniqueness of a generalized solution in the space Cα (G) are considered. A algorithm and numerical method of the solution of an nonlocal problem by means of the Mathcad package is presented.