In a circle with a diameter of 8 decimeters, what is the radius in centimeters?
在一个直径是8分米的圆里，半径是多少厘米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<result>40</result>