To type a manuscript, if the speed of typing per minute is increased by 25%, how much will the working hours be reduced.
打一份稿件，如果每分钟打字的速度提高25%，那么工作时间就会减少多少．
<gadget id="calculator">1 / 1</gadget>
<output>1</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

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

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

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