这样就对了~
public class HelloWorld{
public static void main(String[] args) {
int one = 10 ;
int two = 20 ;
int three = 0 ;
System.out.println(three+=one+two);
System.out.println(three+=one);
System.out.println(three-=one);
System.out.println(three*=one);
System.out.println(three/=one);
System.out.println(three%=one);