static void Main(string[] args) { double[,] ex = new double[3, 3] { { 1, 2, 3 }, { 4, 5, 6 }, { -2, 4, -7 } }; double[,] ex2 = new double[3, 3] { { 2, 3, 4 }, { 4, 5, 6 }, { -2, 4, -7 } }; TSMatrix a = new TSMatrix(3, ex); TSMatrix b = new TSMatrix(3, ex2); TSMatrix c = new TSMatrix(4); a.LowerGreaterValues(); b.GetSum(); (b + a).Output(); }