Xiaohong is 13 years old this year, her grandfather is 9 years younger than 6 times her age, how old is her grandfather this year?
小红今年13岁，爷爷的年龄比她的6倍少9岁，爷爷今年多大？
<gadget id="calculator">13 * 6</gadget>
<output>78</output>

<gadget id="calculator">78 - 9</gadget>
<output>69</output>

<result>69</result>