Undoubtedly Berezin is the farther of "supermathematics" who, based on methods of quantum field theory realised the importance of Grassmann algebras in physics. He realised that one should be able to treat commuting and anticommuting variables on an equal footing from both an algebraic and geometric perspective. Spurred on by the development of supersymmetry, Berezin & Leites in 1975 gave the world the notion of a supermanifold. To understand supermanifolds rigorously one needs tools from algebraic geometry, specifically sheaves and locally ringed spaces. However, a working knowledge can quickly be gained using local coordinates in a way almost identical to smooth manifolds. In this talk, I will sketch the coordinate approach to supermanifolds and present some applications of the theory in differential geometry and physics.