The elder brother and the younger brother are 24 years old this year. The elder brother is 4 years older than the younger brother. How old is the elder brother this year?
哥哥和弟弟今年共24岁，哥哥比弟弟多4岁，哥哥今年多少岁．
<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">24 - 10</gadget>
<output>14</output>

<result>14</result>