Xiao Ming lives on the 3rd floor, and there are 9 steps on each floor. How many steps does Xiao Ming have to walk from downstairs to the 3rd floor after school?
小明家住3楼，每层楼梯有9个台阶，小明放学回家从楼下到3楼，要走多少个台阶？
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<result>18</result>