(1/3): x = (1/5): (6/7).
(1/3)：x=(1/5)：(6/7)．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">(1/3) * (6/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(2/7) / (1/5)</gadget>
<output>10/7 = around 1.428571</output>

<result>10/7 = around 1.428571</result>