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

<style type="text/css"> 
.clear {
  clear: left;
}

.container {
  width: 150px;
  border: 1px solid;  
}

.left {
  float: left;
  width: 100px;
  padding: 10px;
  border: 1px solid;
  text-align: center;
  margin-top: 5px;
  margin-right: 5px;
  margin-bottom: 5px;
  margin-left: 5px;  
}
</style>

<div class="container"> 
  <div class="clear"></div> 
  
  <div class="left">
    1
  </div>
  
  <div class="left">
    2
  </div>  
  
  <div class="left">
    3
  </div>  
  
  <div class="clear"></div>   
</div>

</body>
</html>