Xiaohua is 12 years old this year, and his grandfather will be 5 times his age in 5 years. How old is grandpa now?
小华今年12岁，5年后爷爷是他年龄的5倍．爷爷现在的年龄是多少岁．
<gadget id="calculator">12 + 5</gadget>
<output>17</output>

<gadget id="calculator">17 * 5</gadget>
<output>85</output>

<gadget id="calculator">85 - 5</gadget>
<output>80</output>

<result>80</result>