There are 30 classrooms in the school, each classroom has 6 lamps, and each lamp costs 20 yuan. How much does it cost the school to install classroom lights?
学校有30间教室，每间教室有6盏灯，每盏灯要20元．学校安装教室灯一共要多少元？
<gadget id="calculator">30 * 6 * 20</gadget>
<output>3_600</output>

<result>3_600</result>