What is exponential

Question

how do u write 4**5 in math didn't understand how to it on paper. what is meaning of 2 multiplication since

Answer 1

4**0 = 1
4**1 = 4
4**2 = 4 * 4
4**3 = 4 * 4 * 4
4**4 = 4 * 4 * 4 * 4
4**5 = 4 * 4 * 4 * 4 * 4

Answer 2

4**2.5 = 4**2 * 4**0.5 = 4*4 * √4 = 4*4*2 = 32