The inner circumference of a ring is 12.56 decimeters, and the ring width is 2 cm. What is the area of the ring?
一个圆环它的内圆周长是12.56分米，环宽是2厘米，这个圆环的面积是多少．
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 + (1/5)</gadget>
<output>11/5 = around 2.2</output>

<gadget id="calculator">(11/5) ** 2</gadget>
<output>121/25 = around 4.84</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">(121/25) - 4</gadget>
<output>21/25 = around 0.84</output>

<gadget id="calculator">3.14 * (21/25)</gadget>
<output>2.6376</output>

<result>2.6376</result>