The assumption is that you are asking a question about the mode of statistics (mean, mode, median).

If you know the definition of mode then

you know there can be 1, or 2 or n modes is a set.

To answer your question: Simply count 'em.

Nothing I know could be more simple.

Since the mode(s) can be at BOTH ends of the data set (at the same time), ordering the set doesn't help much.