If (2/7) of a number is 6, what is the number?
一个数的(2/7)是6，那么这个数是多少．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">6 / (2/7)</gadget>
<output>21</output>

<result>21</result>