The diameter of a circle is 2 cm, what is its area in cm**2.
一个圆的直径是2厘米，它的面积是多少厘米**2．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<result>3.14</result>