For a basket of pears, if (1/4) of the selling weight is equal to (1/5) of the remaining weight, then how much does the remaining weight account for in the total.
一筐梨，卖出重量的(1/4)等于剩下重量的(1/5)，则剩下的重量占总量的多少．
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

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

<result>5/9 = around 0.555556</result>