Wang Yun counted the steps as he went upstairs. When he reached the second floor, there were 25 steps. His family lived on the fourth floor. How many more steps did he have to walk?
王云一边上楼一边数台阶，他走到二楼时，有25级台阶，他家住在4楼，还要走多少级台阶．
<gadget id="calculator">4 - 2</gadget>
<output>2</output>

<gadget id="calculator">25 * 2</gadget>
<output>50</output>

<result>50</result>