The radius of a semicircular cardboard is 2 decimeters, what is the perimeter of the cardboard
一个半圆形纸板的半径是2分米，这个纸板的周长是多少分米
<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>