(2/7) of the number A is equal to the number B, the number B is 140, what is the number A?
甲数的(2/7)等于乙数，乙数是140，甲数是多少．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">140 / (2/7)</gadget>
<output>490</output>

<result>490</result>