The older sister and the younger sister have 39 stamps in total. If the older sister gives the younger sister 7 stamps, then the younger sister has 3 less stamps. How many stamps did the younger sister originally have?
姐姐和妹妹共有邮票39枚，如果姐姐给妹妹7枚后就比妹妹少3枚，那么妹妹原来有邮票多少枚．
<gadget id="calculator">3 - 7 - 7</gadget>
<output>-11</output>

<gadget id="calculator">39 + (-11)</gadget>
<output>28</output>

<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">28 / 2</gadget>
<output>14</output>

<result>14</result>