Four years ago Xiaolin was twice as old as Xiaoli. Xiaolin is 16 years old this year. How old is Xiaoli?
四年前小林的年龄是小丽的2倍，小林今年16岁，小丽今年多少岁？
<gadget id="calculator">16 - 4</gadget>
<output>12</output>

<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<result>10</result>