public void clickNumber(Button _button)
        {
        if (decimalExponent == 0)
            number = (number * 10D) + Double.parseDouble(_button.getText().toString());
        else
            {
            double decimal = Double.parseDouble(_button.getText().toString());
            number = number + (decimal / (Math.pow(10D, (double)decimalExponent)) );
            decimalExponent++;
            }
        result.setText(Double.toString(number));
        }