class Jiajianchengchu
{
    public double jia(double c,double b)

    {
        return c+b;
    }

    public double jian(double b,double t)

    {
        return b-t;
    }
    public double cheng(double y,double u)
    {
        return y*u;

    }
    public double chu(double i,double k)
    {
        if(k!=0)
            return i/k;
    }
}