sum总和不等于105

public class HelloWorld{

    public static void main(String[] args) {

int age1=24;

int age2=18;

int age3=36;

int age4=27;

int sum=age1+age2+age3+age4;

double avg=sum/4;

int minus=age1-age2;

int newAge=--age1

   System.out.println("年龄总和："+sum);

    System.out.println("平均年龄："+avg);

System.out.println("年龄差值："+minus);

System.out.println("自减后的年龄："+newAge);

}

}

哪里错了