Divide a square piece of paper into 5 equal parts, cut off one part, and the remaining area occupies ((())/(())) of the original square.
把一张正方形纸片平均分成5份，剪去其中的1份，剩下的面积占原来正方形的((())/(()))．
<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>