The younger brother is 6 years old this year, and the older brother is 10 years old this year. After 10 years, how old is the older brother than the younger brother?
弟弟今年6岁，哥哥今年10岁，10年后，哥哥比弟弟大多少岁．
<gadget id="calculator">10 - 6</gadget>
<output>4</output>

<result>4</result>