Dynamically calculate a div width

[Rain Lover]

Hi,

Here are sample divisions:

<style type="text/css">
#grandparent {width:100px;}
#parent {overflow:auto; height:100px; }
.child {overflow:hidden; margin-left:10px;}
</style>

<div id="grandparent">

<div id="parent">

<div class="child">1000000000000000000000000</div>
<div class="child">1000000000000000000000000</div>
<div class="child">1000000000000000000000000</div>
<div class="child">1000000000000000000000000</div>
<div class="child">1000000000000000000000000</div>
<div class="child">1000000000000000000000000</div>
<div class="child">1000000000000000000000000</div>

</div>

</div>

The <div class="child"> width value is always 10 pixels less than <div id="parent"> width value. How can it be calculated so any width value is given to <div id="parent">, its child gets 10 pixels less than that?

Any help is very much appreciated!
Mike