The radius of the large circle is 3 decimeters, the radius of the small circle is 2 decimeters, and the circumference of the small circle is equal to the circumference of the large circle.
大圆半径是3分米，小圆半径是2分米，小圆周长是大圆周长的多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>