((n)/7)=((m)/3), then when n=2, m=how much.
((n)/7)=((m)/3)，那么当n=2时，m=多少．
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(3/7) * 2</gadget>
<output>6/7 = around 0.857143</output>

<result>6/7 = around 0.857143</result>