The radius of the large circle is 4 times the radius of the small circle. The circumference of the large circle is 12.56 decimeters. What is the radius of the small circle in decimeters?
大圆的半径是小圆半径的4倍，大圆的周长是12.56分米，小圆的半径是多少分米
<gadget id="calculator">12.56 / 2 / 3.14</gadget>
<output>2</output>

<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>