Математическая библиотека? :D

//
public class untitled {
    public static void main (String[] args) {
        System.out.print("module: "+Mathematics.module(-14)+"\t "+"power: "+Mathematics.power(2,3)
        + "\t"+"area : "+Mathematics.area(2,5)+ "\t "+"length : "+ Mathematics.length(4) );
    }
//
public  class  Mathematics {

    public static int module(int num){
        String  str = String.valueOf(num);
        String tmp = "";
        for(String n: str.split("")){
            if(!n.equals("-"))
                tmp = tmp + n;
        }
        int numm;
        numm = Integer.valueOf(tmp);
        return numm;
    }

    public static double power (double num, double pow){
        double n = 1;
        for(int i = 0; i < pow; i++){
            n = n*num;
        }
        return n;
    }

    public static double area (double width, double height){
        return (width*height);
    }

    public static double length (double radius){
        double pi = 3.14;
        return radius*2*pi;
    }
}