If the water consumption of a chemical plant this year is (1/5) that of last year, how much water is saved this year compared to last year?
化工厂今年的用水量是去年的(1/5)，则今年比去年节约用水多少．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>