关于变量简单的运算符

<script>                                
       var x = 50;                      
       var y = x+10;                    
       var z = x-8;                     
       var m = x*5;                     
       var n = x/6;                     
       var k = x%6;                     
       var i = 10;                      
       i++;                             
       var j=10;                        
       j--;                             
       document.write('x的值：'+x+'<br>'); 
       document.write('y的值：'+y+'<br>'); 
       document.write('z的值：'+z+'<br>'); 
       document.write('m的值：'+m+'<br>'); 
       document.write('n的值：'+n+'<br>'); 
       document.write('k的值：'+k+'<br>'); 
       document.write('i的值：'+i+'<br>'); 
       document.write('j的值：'+j+'<br>'); 
 </script>