What is the circumference of a semicircle with a diameter of 2 meters?
直径是2米的半圆，它的周长是多少米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

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

<gadget id="calculator">3.14 + 2</gadget>
<output>5.14</output>

<result>5.14</result>