How to calculate this square root?

I don't know how to calculate this type of number. Because of the limitations of the keyboard, I can't type how it looks, so try to envision what I'm saying. I have the following number: 2.7183. In the upper right corner of that number (like where you'd see a little 2 if you were squaring it), is (-.05 X 1). The answer to the problem is known. It is .9512. I'm trying to figure out how you calculate these types of numbers (where you have a negative decimal value in the upper right corner instead of a "2" to square it or a "3" to cube it, etc)