A classroom has a whiteboard which is shared between the 4 teachers who take turns using the classroom. Each teacher has 2 lessons per day and uses the whiteboard in each lesson. If the whiteboard is cleaned 3 times per lesson, how many times is the whiteboard cleaned in a day?
In one day, there are a total of 4 teachers * 2 lessons each = 
<gadget id="calculator">4*2</gadget>
<output>8</output>
8 lessons.
The whiteboard is therefore cleaned 8 lessons * 3 cleans per lesson = 
<gadget id="calculator">8*3</gadget>
<output>24</output>
24 times.

<result>24</result>