Horizontally align divs

HTML

<div id="start" class="side">
   
</div>
<div id="range"></div>
<div id="end" class="side">
    
</div>

CSS

div { height: 45px; }
div.side {
    background-color: skyblue;
    width: 72px;
    float: left;
}
div#range {
    background-color: tomato;
    width: 216px;
    float: left;
}
span {
    width:100%;
    text-align: center;
    display: block;
    margin: 3px auto;
    /* background-color: gold; */
}