Add milk to egg to make 1/2 cup. Put biscuit mix, sugar, and margarine in a bowl. Add just enough liquid to make a soft dough. Stir briskly. Turn onto floured surface, knead 8-10 times. Roll out 1/2 inch thick. Cut out with cutters. Place on ungreased baking sheet. Place close together for soft side biscuits and apart for crusty biscuits. Bake at 450 for 8 to 10 minutes.