need help in calculation C#

Question

i have a problem to do calculation part.
i need to do 3 calculation part.
Now my problem is , my answer for conf and lift loop many times.
may i know how to correct it?

below are my coding:

 string b = txtTotalItems.Text;
 double e = Double.Parse(b);
 double a;
  double conf;
 double lift;
           
          
                    richTextBox8.Clear();
          foreach (double SuppB in list10)
           
            {
               richTextBox7.Clear();
                foreach (double SuppA in list9)
                {
                    richTextBox9.Clear();
                    foreach (double wee in list8)
                    {
                        a= (wee / e) * 100;
                        richTextBox9.AppendText(string.Format("{0:n2}", a) + "\n");
                      
                        conf = a/ (SuppA / e);
                        richTextBox7.AppendText(string.Format("{0:n2}", conf) + "\n");
                     
                        lift = conf / (SuppB / e) / 100;
                        richTextBox8.AppendText(string.Format("{0:n2}", lift) + "\n");
                       

                    }

                }
            }
hope anyone can help me..