I am 9 years old this year, and the combined age of my grandfather and I is exactly 8 times that of 9. How old is grandpa?
我今年9岁，我和爷爷的岁数加起来刚好是9的8倍．爷爷今年多少岁？
<gadget id="calculator">9 * 8</gadget>
<output>72</output>

<gadget id="calculator">72 - 9</gadget>
<output>63</output>

<result>63</result>