In what four states does matter exists?

Answer 1

We generally consider the 4 states of matter to be:

Solid

Liquid

Gas

Plasma

Supercritical fluids are sort of both liquids and gases but are more often than not grouped with "gas"

We might also want to include Bose-Einstein condensate as another state of matter. In a Bose-Einstein condensate, extremely cold atoms clump together and act as if they were a single atom.

Answer 2

The four states of matter are liquid, solid, gas, and plasma. The three states of matter solid, liquid, and gas are more commonly known, but plasma exists. Lightning is an example of plasma.