A number divided by (9/7) is equal to the reciprocal of (18/7), find this number.
一个数除以(9/7)等于(18/7)的倒数，求这个数．
<gadget id="calculator">18 / 7</gadget>
<output>18/7 = around 2.571429</output>

<gadget id="calculator">1 / (18/7)</gadget>
<output>7/18 = around 0.388889</output>

<gadget id="calculator">9 / 7</gadget>
<output>9/7 = around 1.285714</output>

<gadget id="calculator">(7/18) * (9/7)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>