What is the circumference of a semicircle with a diameter of 7 cm?
直径是7cm的半圆形，它的周长是多少cm．
<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">3.14 * (7/2)</gadget>
<output>10.99</output>

<gadget id="calculator">10.99 + 7</gadget>
<output>17.99</output>

<result>17.99</result>