There are 10 candles in a room, how many candles are left after blowing out 7?
屋子里有10根蜡烛，吹灭7根后还剩多少根蜡烛．
<gadget id="calculator">10 - 7</gadget>
<output>3</output>

<gadget id="calculator">3 + 7</gadget>
<output>10</output>

<result>10</result>