[css] Calculating width from percent to pixel then minus by pixel in LESS CSS

I will calculate width in some element from percent to pixel so I will minus -10px via using LESS and calc(). It´s possible?

div {
    span {
        width:calc(100% - 10px);
    }
}

I using CSS3 calc() so it doesn't work: calc(100% - 10px)

Example: if 100% = 500px so width = 490px (500-10);

I made a demo for testing : http://jsfiddle.net/4DujZ/55/

so padding will say: 5 (10px / 2) all the time when I resizing.

Can I do it in LESS? I know how to do in jQuery and simple CSS like margin padding or else... but i will try to do functional in LESS with calc()

I think width: -moz-calc(25% - 1em); is what you are looking for. And you may want to give this Link a look for any further assistance

Try this :

width:auto;
margin-right:50px;

Or, you could use the margin attribute like this:

    {
    background:#222;
    width:100%;
    height:100px;
    margin-left: 10px;
    margin-right: 10px;
    display:block;
    }