There are two ropes, the first one is (2/7) meters long and the second one is (4/7) meters long, which one is longer? How many meters long?
有两根绳子，第一根长(2/7)米，第二根长(4/7)米，哪一根绳子长？长多少米？
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(4/7) - (2/7)</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>