The age of Xiaogang and Xiaoyou this year is 21 years old. After 5 years, Xiaogang will be 3 years older than Xiaoyou. How old is Xiaogang this year?
今年小刚和小友的年龄和是21岁，5年后小刚比小友大3岁，今年小刚多少岁．
<gadget id="calculator">21 + 3</gadget>
<output>24</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<result>12</result>