The teachers give the students 6 regular classes a day, and each class is calculated as 45 minutes. How many minutes are the six classes?
老师们一天给同学们上6节正课，每节按45分钟计算，六节课是多少分钟．
<gadget id="calculator">45 * 6</gadget>
<output>270</output>

<result>270</result>