Calculating a range based on a fixed percent

[dprobst]

I need to calculate a range (tolerance limit) for a set standard based on a set percentage. For example, if I have a standard of 30 with a tolerance limit of 4%, I need to create a cell that will calculate and display the range of 28.8 - 31.2. Both the percentage and the standard will change based on what is being tested, so I need a calculation that will automatically display the tolerance limit based on whatever
standard and percentage appears on that line in the spreadsheet.

Thanks.

[protonLeah]

cell for the lower limit: cell with Standard value * (1 - cell with tolerance)
e.g.
in A1: =V1 * (1 - F1)

etc...