Divide a 2-meter-long rope into 5 or 7 sections on average, what is the difference between each section?
把一根2米长的绳子平均分成5段或7段，每段相差多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">(2/5) - (2/7)</gadget>
<output>4/35 = around 0.114286</output>

<result>4/35 = around 0.114286</result>