Practicas faciles en visual c#

namespace PRACTICA_2_jose_A
{
public partial class Form1 : Form
{
int a;
public Form1()
{
InitializeComponent();

}
private voidJsa_Click(object sender, EventArgs e)
{
a = Int32.Parse(Js.Text);
Ja.Text="el numero es " + a;
}

private void Jsa_Click()
{}

private void jesa_Click(object sender, EventArgs e)
{
Application.Exit();
}

private void clear_Click(object sender, EventArgs e)
{Js.Focus();
Js.Clear();
}


}
}

namespace practik3js
{
public partial class Form1 : Form
{
double a, b;public Form1()
{
InitializeComponent();
}

private void bttsuma_Click(object sender, EventArgs e)
{
a = double.Parse(n1.Text);
b= double.Parse(n2.Text);
result.Text = "la suma es " + (a + b);
}

private void bttlimpiar_Click(object sender, EventArgs e)
{
n1.Clear();n1.Focus();
n2.Clear();
n2.Focus();

}

private void bttexit_Click(object sender, EventArgs e)
{Application.Exit();
}
}
}

namespace practica4js
{
public partial class Form1 : Form
{
double a;
double b;
public Form1()
{InitializeComponent();
}

private void button5_Click(object sender, EventArgs e)
{

}

private void suma_Click(object sender, EventArgs e)
{
a =double.Parse(textBox1.Text);
b = double.Parse(textBox2.Text);
result.Text = "el eresultado es " + (a+b);
}

private void resta_Click(object sender,...