What is the perimeter of a square whose side length is (5/7) decimeters?
边长为(5/7)分米的正方形的周长是多少分米．
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(5/7) * 4</gadget>
<output>20/7 = around 2.857143</output>

<result>20/7 = around 2.857143</result>