SOURCE

    <div class="left">111</div>
    <div class="center">222</div>
    <div class="right">333</div>

.left{
    width: 200px;
    background-color: red;
    height: 300px;
    float:left;
}
.center{

    background-color: orange;
    margin-left: 100px;
    height: 300px;
    margin-right: 100px;
}
.right{
    width: 200px;
    float:right;
    height: 300px;
    background-color: red;
}