A fence is surrounded by a circular flower bed with a circumference of 125.6 meters. The fence is 5 decimeters wide from the circular flower bed. How long is the fence?
在一块周长是125.6米的圆形花坛周围围一圈篱笆，篱笆离圆形花坛5分米宽，篱笆长多少米？
<gadget id="calculator">125.6 / 3.14 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 + 0.5</gadget>
<output>20.5</output>

<gadget id="calculator">2 * 3.14 * 20.5</gadget>
<output>128.74</output>

<result>128.74</result>