Bit

A bit represents a single binary digit, which may be either 1 or 0 (sometimes also referred to as High or Low).

8 bits is known as a byte.

Because one bit has 2 states (0 or 1),
 * 2 bits have 4 states - 00, 01, 10, 11 (2^2)
 * 3 bits have 8 states - 000, 001, 010, 011, 100, 101, 110, 111 (2^3)
 * 4 bits have 16 states, (2^4)
 * 5 bits have 32 states, (2^5)
 * 6 bits have 64 states, (2^6)
 * 7 bits have 128 states, (2^7)
 * 8 bits have 256 states, (2^8)
 * 9 bits have 512 states, (2^9)
 * and so on, doubling each step.

So the amount of states is equal to 2^x where x is the number of bits.