<div class="wrapper">
<div class="middle">
<div class = "inside">middle</div>
</div>
<div class="left">left</div>
<div class="right">right</div>
</div>
.inside{
margin:0 100px 0 100px
}
.middle{
background-color:lightblue;
width:100%;
float:left;
}
.left{
width:100px;
background-color:lightpink;
float:left;
margin-left:-100%;
}
.right{
width:100px;
background-color:lightgreen;
float:left;
margin-left:-100px
}