Question

What is 5 to the negative fourth power

Answer 1

You can write 5 to the negative fourth power as 5^(-4). In cases, when you have negative power, you just have to put 5^4 in the denominator. So, instead of 5^(-4), you have 1/(5^4). 
5^4 equals to 625. 
In the last step you have to divide 1 by 625.

The result is 0.0016.

Answer 2

5×-5= -25×-5= 125×-5= -625. Answer: -625