- A ring, the outer circumference is 12.56 meters, the inner circumference is 9.42 meters, how many meters is this ring wide?
-个圆环，外圆周长是12.56米，内圆周长是9.42米，这个圆环宽多少米．
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

<gadget id="calculator">9.42 / 3.14 / 2</gadget>
<output>1.5</output>

<gadget id="calculator">2 - 1.5</gadget>
<output>0.5</output>

<result>0.5</result>