Hex, Bin, Dec Calculator

private System.Windows.Forms.GroupBox groupBox1;
        private System.Windows.Forms.RadioButton radioButton3;
        private System.Windows.Forms.RadioButton radioButton2;
        private System.Windows.Forms.RadioButton radioButton1;
        private System.Windows.Forms.Button btnbsp;
        private System.Windows.Forms.TextBox calci;
        private System.Windows.Forms.Button btnD;
        private System.Windows.Forms.Button btnE;
        private System.Windows.Forms.Button btnF;
        private System.Windows.Forms.Button btnA;
        private System.Windows.Forms.Button btnB;
        private System.Windows.Forms.Button btnC;
        private System.Windows.Forms.Button btn1;
        private System.Windows.Forms.Button btn2;
        private System.Windows.Forms.Button btn3;
        private System.Windows.Forms.Button btn4;
        private System.Windows.Forms.Button btn5;
        private System.Windows.Forms.Button btn6;
        private System.Windows.Forms.Button btn7;
        private System.Windows.Forms.Button btn9;
        private System.Windows.Forms.Button btndot;
        private System.Windows.Forms.Button btn0;
        private System.Windows.Forms.Button btneql;
        private System.Windows.Forms.Button btnclr;
        private System.Windows.Forms.Button btn8;
        private System.Windows.Forms.Button btnsub;
        private System.Windows.Forms.Button btnmul;
        private System.Windows.Forms.Button btnadd;
        private System.Windows.Forms.Button btndiv;
        
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication4
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 bool plus = false;
        bool minus = false;
        bool multiply = false;
        bool divide = false;
        private void btn1_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "1";
        }

        private void btn2_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "2";
        }

        private void btn3_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "3";
        }

        private void btn4_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "4";
        }

        private void btn5_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "5";
        }

        private void btn6_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "6";
        }

        private void btn7_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "7";
        }

        private void btn8_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "8";
        }

        private void btn9_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "9";
        }

        private void btn0_Click(object sender, EventArgs e)
        {
            calci.Text = calci.Text + "0";
        }

        private void btndot_Click(object sender, EventArgs e)
        {
            if (calci.Text.Contains("."))
            {
                return;
            }
            else
            {
                calci.Text = calci.Text + ".";
            }
        }

        private void btndiv_Click(object sender, EventArgs e)
        {
            if (calci.Text == "")
            {
                return;
            }
            else
            {
                divide = true;
                calci.Tag = calci.Text;
                calci.Text = "";
            }
        }

        private void btnmul_Click(object sender, EventArgs e)
        {
            if (calci.Text == "")
            {
                return;
            }
            else
            {
                multiply = true;
                calci.Tag = calci.Text;
                calci.Text = "";
            }
        }

        private void btnsub_Click(object sender, EventArgs e)
        {
            if (calci.Text == "")
            {
                return;
            }
            else
            {
                minus = true;
                calci.Tag = calci.Text;
                calci.Text = "";
            }
        }

        private void btnadd_Click(object sender, EventArgs e)
        {
            if (calci.Text == "")
            {
                return;
            }
            else
            {
                plus = true;
                calci.Tag = calci.Text;
                calci.Text = "";
            }
        }

        private void btneql_Click(object sender, EventArgs e)
        {
            if (plus)
            {
                decimal dec = Convert.ToDecimal(calci.Tag) + Convert.ToDecimal(calci.Text);
                calci.Text = dec.ToString();
            }
            else if (minus)
            {
                decimal dec = Convert.ToDecimal(calci.Tag) - Convert.ToDecimal(calci.Text);
                calci.Text = dec.ToString();
            }
            else if (multiply)
            {
                decimal dec = Convert.ToDecimal(calci.Tag) * Convert.ToDecimal(calci.Text);
                calci.Text = dec.ToString();
            }
            else if (divide)
            {
                decimal dec = Convert.ToDecimal(calci.Tag) / Convert.ToDecimal(calci.Text);
                calci.Text = dec.ToString();
            }
            return;
        }

        private void btnclr_Click(object sender, EventArgs e)
        {
            calci.Text = "";
        }

        private void btnbsp_Click(object sender, EventArgs e)
        {
            if (calci.Text.Length > 0)  

         calci.Text = calci.Text.Remove(calci.Text.Length - 1); 

        }

Im doing project in my training that is a calculator using hexa decimal, binary, decimal using radio button to select each I getting only decimal like basic calculator but how to get binary and hexa decimal will done please tell any body