Tashi is 9 years old this year, his father is 4 times as old as Tashi, and his grandfather is 8 times as old as Tashi. How old is grandpa than his father?
扎西今年9岁了，爸爸的年龄是扎西4倍，爷爷的年龄是扎西的8倍，爷爷比爸爸大多少岁？
<gadget id="calculator">9 * 8</gadget>
<output>72</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<gadget id="calculator">72 - 36</gadget>
<output>36</output>

<result>36</result>