What is the circumference of a semicircle whose diameter is 6 decimeters?
一个直径是6分米的半圆，它的周长是多少分米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3.14 * 3</gadget>
<output>9.42</output>

<gadget id="calculator">9.42 + 6</gadget>
<output>15.42</output>

<result>15.42</result>