Question

If black holes are a considered to be a singularity, how can one be larger than the other?

Answer 1

Black holes have mass.

Explanation:

It is thought that there is a singularity at the centre of a black hole. This is a point of infinite curvature of space-time and defies the laws of physics as we know it. A black hole is more than the singularity. It has mass, charge and spin. If two black holes merge they form a bigger black hole.