A number (5/9) is 5.5 more than 10.5 (3/7), find this number. (solution by equation)
一个数的(5/9)比10.5的(3/7)多5.5，求这个数．(用方程解)
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">10.5 * (3/7)</gadget>
<output>4.5</output>

<gadget id="calculator">4.5 + 5.5</gadget>
<output>10</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">10 / (5/9)</gadget>
<output>18</output>

<result>18</result>