6 х 6 х 6 х 6 х 6 is the same as 6⁵. Exponential form is when your multiply a number a certain amount of times but you want to put it where it makes it easier to read. In this equation we are multiply six, five times. An exponent essentially shows how many times you multiply that number.
6 х 6 х 6 х 6 х 6 = 7,776
6⁵ = 7,776
Best of Luck!