Xiao Dong's house is on the 8th floor, and it takes Xiao Dong 15 seconds to go up each floor. How many seconds does it take him to get home from the first floor?
小东家在8楼，小东每上一层楼用15秒，他从一楼到家需要多少秒．
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">15 * 7</gadget>
<output>105</output>

<result>105</result>