A residential building has seven floors, and there are 15 stairs between every two floors. How many steps did Jiajia walk from the 1st floor to the 7th floor?
一幢住宅楼有七层，每两层之间的楼梯有15级，佳佳从1楼到7楼，共走了多少级台阶．
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">15 * 6</gadget>
<output>90</output>

<result>90</result>