The radius of the small circle is (2/3) of the radius of the large circle, and the area of the small circle is the area of the large circle
小圆半径是大圆半径的(2/3)，小圆面积是大圆面积的多少
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>