Celebrities are often reluctant to reveal their ages, and journalists want to know anything the reader wants to know. A reporter asked a celebrity: "How old are you?" Five times the age of years ago, which is exactly equal to my current age." Please do the math, how old is this star this year.
明星通常都不愿说出自己的年龄，记者则想知道读者希望了解的任何事情．记者问一位明星："您今年多少岁？"这位明星不愿意直截了当回答，又不喜欢说假话糊弄人，就拐弯抹角地说："用我5年后岁数的5倍，减去我5年前的岁数的5倍，刚好等于我现在的岁数．"请你算算，这位明星今年多少岁．
<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">25 + 25</gadget>
<output>50</output>

<gadget id="calculator">1 - 5</gadget>
<output>-4</output>

<gadget id="calculator">5 + (-4)</gadget>
<output>1</output>

<gadget id="calculator">50 / 1</gadget>
<output>50</output>

<result>50</result>