(1/5) of a number is 6, what is (3/7) of this number.
一个数的(1/5)是6，这个数的(3/7)是多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">6 / (1/5)</gadget>
<output>30</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">30 * (3/7)</gadget>
<output>90/7 = around 12.857143</output>

<result>90/7 = around 12.857143</result>