The age of grandpa this year is 8 times of the average age. After 4 years, the age of grandpa will be 6 times of the average age. How old is grandpa this year?
今年爷爷的年龄是平平年龄的8倍，4年后，爷爷的年龄是平平年龄的6倍，今年爷爷多少岁．
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<gadget id="calculator">8 - 6</gadget>
<output>2</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<result>80</result>