One way:

A1: 108.25
A2: =A1/(1 + 8.25%)

or, equivalently:

A2: =A1/(1.0825)

In article ,
www.javysgifts.com
wrote:

I live in South Texas and our sales taxes is 8.25%. I am trying to come up
with the formula for figuring out the total amount of sale before tax when
taxes have already been added to it. For Example: If total sales were
$108.25 including the taxes what was the total sales before taxes. I know
the answer is $100, however what is the formula to get it.