How to use of Operator in java

// main class
public class second
{
// main function
public static void main(String args[])
{
//variable declaration
int a,b,c,d,e,f;
a=30;
b=20;
// operator use 
c=a*b;
d=a+b;
e=a-b;
f=a/b;
// print function
System.out.println("a*b="+c);
System.out.println("a+b="+d);
System.out.println("a-b="+e);
System.out.println("a/b="+f);
}
}

output : a*b : 600;
             a+b : 50;
             a-b :  10;
             a/b :   1.5;