You will already be familiar with the notation for squares and cubes:
a2 = a x a and a3 = a x a x a
and this is generalised by defining:
an = a x a x...x a (n times a)
That is, powers are used to describe the result of repeatedly multiplying a number by itself.
The number that is successively multiplied by itself is called the base. A small raised number called an exponent follows the base and indicates the number of times the base is to be multiplied.
Any number (except 0) raised to the zero power is equal to 1.