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 calculator
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
            private void  AC (object sender, EventArgs e)
            {
                textBox1.Text = "";
            }   
            private void  = (object sender, EventArgs e)
            {
                DataTable dt = new DataTable();
                textBox1.Text = dt.Compute(textBox1.Text, "").ToString();            
            }
            private void  1 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "1";
            }
            private void  2 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "2";
            }
            private void  3 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "3";
            }
            private void  4 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "4";
            }
            private void  5 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "5";
            }
            private void  6 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "6";
            }
            private void  7 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "7";
            }
            private void  8 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "8";
            }
            private void  9 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "9";
            }
            private void  0 (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "0";
            }
            private void  . (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + ".";
            }
            private void  + (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "+";
            }
            private void  - (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "-";
            }
            private void  * (object sender, EventArgs e)
            {   
                textBox1.Text = textBox1.Text + "*";
            }
            private void  / (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "/";
            }
            private void  % (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "%";
            }
            private void  +/- (object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + "+/-";
            }
        }
    }