The old man said: "Add 12 to my age, divide by 4, then subtract 15, and multiply by 10, which is exactly 80 years old." How old is this old man now?
老爷爷说："把我的年龄加上12，再用4除，然后减去15，再乘以10，恰好是80岁．"这位老爷爷现在有多少岁．
<gadget id="calculator">80 / 10</gadget>
<output>8</output>

<gadget id="calculator">8 + 15</gadget>
<output>23</output>

<gadget id="calculator">23 * 4</gadget>
<output>92</output>

<gadget id="calculator">92 - 12</gadget>
<output>80</output>

<result>80</result>