If a circle with a diameter of 10 cm is cut into two semicircles, what is the sum of the circumferences of the two semicircles?
把一个直径10厘米的圆剪成两个半圆，则两个半圆周长的和是多少厘米．
<gadget id="calculator">3.14 * 10</gadget>
<output>31.4</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">31.4 + 20</gadget>
<output>51.4</output>

<result>51.4</result>