If a circular iron ring with a length of 16 decimeters is used to make a circular iron ring, the joint is 0.3 decimeters. What is the diameter of the iron ring in decimeters?
用一根长16分米的铁丝做一个圆形铁圈接头处是0.3分米，这个铁圈的直径是多少分米？
<gadget id="calculator">16 - 0.3</gadget>
<output>15.7</output>

<gadget id="calculator">15.7 / 3.14</gadget>
<output>5</output>

<result>5</result>