Jav取平均值并保留两位小数

public static void main(String[] args) {
    List<String> aa1 = new ArrayList<>();
    ss(0.05,4,aa1);
    System.out.println(aa1);
    List<String> aa2 = new ArrayList<>();
    ss(0.01,5,aa2);
    System.out.println(aa2);
}

public static void ss(double price,int num,List<String> aa){
    Double temp = NumberUtil.roundDown(NumberUtil.div(price, num), 2).doubleValue();
    aa.add(temp.toString());
    System.out.println(temp);
    if (num==1) {
    } else {
        ss(price-temp,num-1,aa);
    }
}