Grandpa is 75 years old this year, exactly three times the age of my brother and I. I am 9 years old this year, how old is my brother?
爷爷今年75岁，正好是我和哥哥的年龄的3倍，我今年9岁，哥哥今年多少岁．
<gadget id="calculator">75 / 3</gadget>
<output>25</output>

<gadget id="calculator">25 - 9</gadget>
<output>16</output>

<result>16</result>