(2/3): x=(4/7): 6.
(2/3)：x=(4/7)：6．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) * 6</gadget>
<output>4</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">4 / (4/7)</gadget>
<output>7</output>

<result>7</result>