A certain class cleans, (2/3) of the whole class cleans the classroom, (1/4) cleans the dry area, and the rest clean the glass. What percentage of the class are those who clean the glass?
某班打扫卫生，全班人数的(2/3)扫教室，(1/4)扫包干区，剩下的人擦玻璃．擦玻璃的人占全班人数的几分之几？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/3) - (1/4)</gadget>
<output>1/12 = around 0.083333</output>

<result>1/12 = around 0.083333</result>