There are about 5 drops in 1 milliliter of water, and there are 50 people in the class. If each person saves 20 drops of water per day, how many milliliters of water can the whole class save in total?
1毫升水大约有5滴，全班50人．每人每天节约20滴水，全班每天共节约多少毫升水？
<gadget id="calculator">20 / 5</gadget>
<output>4</output>

<gadget id="calculator">4 * 50</gadget>
<output>200</output>

<result>200</result>