count.java

public class suanshu {

        //编写一个main方法

        public static void main(String[ ] args) {

                int n1 = 13;

                int n2 = 17;

                int n3 = n1 + n2;

                System.out.println("n3 = " + n3);//30

                int n4 = 38;

                int n5 = n4 - n3;

                System.out.println("n5 = " + n5);//8

        }

}