If a semicircular iron plate has a radius of 2 cm, what is its circumference in cm?
一个半圆的铁片，它的半径是2cm，它的周长是多少cm．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">2 * 3.14 * 1</gadget>
<output>6.28</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">6.28 + 4</gadget>
<output>10.28</output>

<result>10.28</result>