It used to take 20 hours to go to grandma's house. Now the speed of the train has been increased, and it will arrive in 16 hours. How much time is saved by taking the train to grandma's house now?
以前去奶奶家要用20小时．现在火车提速了，16小时就能到．现在乘火车去奶奶家的时间比原来节省了百分之几？
<gadget id="calculator">20 - 16</gadget>
<output>4</output>

<gadget id="calculator">4 / 20</gadget>
<output>1/5 = around 0.2</output>

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