Subtracting Tax & NI from Gross Formula

[Shazz]

I wonder if anyone can help me at all, I have a spread sheet and I want to be able to Take Tax & NI awy from a gross total, leaving the net, please see below.

A1 A2 A3 A4
Gross Tax NI Net
70.47 20% 11% Formula Total Here

I am a newbie so I need a simple Way please.

Thanks to anyone who can help.

Shazz
xx

 

[BarCodeWiz]

Something like this?
(I'm assuming you have the data in row 1; in cells A1,B1,C1)

=A1-B1*A1-C1*A1

 

[BarCodeWiz]

Noticed my mistake after posting. I think what you need is something like this:

=A1/(1+B1+C1)