This year, the combined age of Qin Fen and his mother is 40 years old, and the age of his mother is four times that of Qin Fen. How old is Qin Fen?
今年秦奋和妈妈的年龄加在一起是40岁，妈妈的年龄是秦奋年龄的4倍，那秦奋是多少岁．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">40 / 5</gadget>
<output>8</output>

<result>8</result>