How to align DIV tag side by side using CSS

<div id="brandinghome">    
        <div class="box round first">
            <h2>Form</h2>
            <div class="block"> 
		<div style="text-align:left">         
                    <table class="form"> 
			<tr>
                            <td>  
                                <label>Description</label>
                                <input id="description" type="text" />
                            </td>
                        </tr>
		    </table>
                </div>

		<div style="text-align:right">
                    <div id="myMap" style="height:400px; width:50%">
                    </div> 
                </div>
	    </div>
	</div>
</div>

above code not working in content. when i used 

<div style="float:right">

then

<div id="brandinghome">    
        <div class="box round first">
            <h2>Form</h2>
            <div class="block"> 

above tag not working.