We know that a teaspoonfull of the mass of a black hole would weigh nearly a mountain on Earth. But when a star collapses into a black hole in a supernova. The pieces of the star fly off in the space. So does the mass of the star equal the mass of the black hole? Ideally it should not. But how much mass goes in to make the black hole and how much of the mass gets wasted or spread out in pieces in space?