Xiao Ming's house is on the seventh floor, with 18 steps on each floor. How many steps does Xiao Ming have to walk from the first floor to the fifth floor?
小明家在第7层楼，每层18级台阶．小明从第一层走到第五层要走多少级台阶．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">18 * 4</gadget>
<output>72</output>

<result>72</result>