Mom turns on the air conditioner at 8:00 p.m. and sets it to turn off at 3:00 a.m. How many hours will the air conditioner work.
妈妈晚上8时开空调，设定凌晨3时关机．空调将工作多少小时．
<gadget id="calculator">8 + 12</gadget>
<output>20</output>

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

<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<result>7</result>