My elder brother is 4 years older than my younger brother this year. Eight years ago, my elder brother was twice as old as my younger brother. How old is my elder brother this year?
哥哥今年比弟弟大4岁，8年前，哥哥的年龄是弟弟的2倍，哥哥今年多少岁？
<gadget id="calculator">2 - 1</gadget>
<output>1</output>

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

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">8 + 8</gadget>
<output>16</output>

<result>16</result>