If the number of girls in a class is reduced (1/5), it will be equal to the number of boys. It is wrong to say that there are more girls than boys.
某班女生人数，如果减少(1/5)，就与男生人数相等，下面女生比男生多多少是错的．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 * (4/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) / 1</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>