internal void Backspace()
{
if (EnteringOperand0)
{
if (Operand0 != "0")
{
Operand0 = Operand0.Remove(Operand0.Length - 1);
}
if (Operand0.Length == 0)
{
Operand0 = "0";
}
}
else if (EnteringOperand1)
{
if (Operand1 != "0")
{
Operand1 = Operand1.Remove(Operand1.Length - 1);
}
if (Operand1.Length == 0)
{
Operand1 = "0";
}
}
}