There are 18 steps to go up each floor. Xiaohua's family lives on the fourth floor. How many steps do you have to walk?
每上一层楼要走18级台阶，小华家住在四楼，要走多少级台阶．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">18 * 3</gadget>
<output>54</output>

<result>54</result>