simple calculator that shows the different between 2 numbers in C#

first of all sorry for my broken language. i would like to create a calculator that shows the different between 2 numbers in C# i tried to make it but i always end up with adding the textbox 1 to the textbox 2 and displaying the total in text box 3, which i don't want to do please see the GUI , it's simple i also would like to make the number in green color if the different is positive and red if the different is negative. see the picture thanks! simple gui

Solution

Write this code in the click event of calculate button

    private void Calculate_Click(object sender, EventArgs e)
    {
        if (textBox1.Text != "" && textBox2.Text != "")
        {
            int diff = (Convert.ToInt32(textBox1.Text) - Convert.ToInt32(textBox2.Text));
            textBox3.Text = diff.ToString();
            if (diff >= 0)
            {
                textBox3.ForeColor = Color.Green;
            }
            else
                textBox3.ForeColor = Color.Red;

        }
        else
        {
            MessageBox.Show("PLZ Enter the balances");
        }
    }