The circumference of the large circle is twice that of the small circle, and the diameter of the small circle is equal to that of the large circle.
大圆的周长是小圆的2倍，小圆的直径是大圆的多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>