为什么这个就可以了

public class HelloWorld{
    phttps://www.imooc.com/code/1298#editor-tabs-javaublic static void main(String[] args) {
     int one = 10 ;
        int two = 20 ;
        int three = 0 ;
        int three1=one+two;
        three1=30;
        int three2=three1+one;
        three2=40;
        int three3=three2-one;
        three3=30;
        int three4=three3*one;
        three4=300;
        int three5=three4/one;
        three5=30;
        int three6=three5%one;
        three5=0;
        System.out.println("three=one+two:"+three);
        System.out.println("three+=one:"+three);
        System.out.println("three-=one:"+three);
        System.out.println("three*=one:"+three);
        System.out.println("three/=one:"+three);
        System.out.println("three%=one:"+three);