public static void Open(Mode mode)
{
var f = new FormCalc();
f.CurrentMode = mode;
f.ModeLabel.Text = f.GetModeString(mode);
f.ShowDialog();
}
private void DivButton_Click(object sender, EventArgs e) => FormCalc.Open(FormCalc.Mode.Div);
private void MultiButton_Click(object sender, EventArgs e) => FormCalc.Open(FormCalc.Mode.Multi);
private void MinusButton_Click(object sender, EventArgs e) => FormCalc.Open(FormCalc.Mode.Minus);
private void AddButton_Click(object sender, EventArgs e) => FormCalc.Open(FormCalc.Mode.Add);