A number plus 40% equals 28, find this number.
一个数加上40%等于28，求这个数．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">28 / (7/5)</gadget>
<output>20</output>

<result>20</result>