The younger sister has 5 books, and the older sister has 19 books. After the older sister gives the younger sister a few books, the younger sister has twice as many books as the older sister?
妹妹有5本书，姐姐有19本，姐姐给妹妹几本后，妹妹的书是姐姐的两倍？
<gadget id="calculator">19 + 5</gadget>
<output>24</output>

<gadget id="calculator">24 / 3</gadget>
<output>8</output>

<gadget id="calculator">19 - 8</gadget>
<output>11</output>

<result>11</result>