<html>
<head>
  <title>Div example</title>
</head>
<body>

<style type="text/css"> 
.container{
  float: left;
  clear: left;
  border: 1px dotted;
  width: 366px;
}

.left {
  float: left;
  width: 120px;
  height: 40px;
  border: 1px solid;
}
</style>

<div class="container">
  header
</div>

<div class="container">
  <div class="left">
    1
  </div>
  <div class="left">
    2
  </div>
  <div class="left">
    3
  </div>    
</div>
<div class="container">
  <div class="left">
    4
  </div>
  <div class="left">
    5
  </div>
  <div class="left">
    6
  </div>    
</div>
<div class="container">
  <div class="left">
    7
  </div>
  <div class="left">
    8
  </div>
  <div class="left">
    9
  </div>    
</div>

<div class="container">
  footer
</div>


</body>
</html>