The diameter of a circle is 5 meters, what is the circumference of the semicircle?
一个圆的直径是5米，这个半圆的周长是多少米．
<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">3.14 * (5/2)</gadget>
<output>7.85</output>

<gadget id="calculator">7.85 + 5</gadget>
<output>12.85</output>

<result>12.85</result>