In order to maintain life, each person needs about 2.5 liters of water per day, and how many liters of water do 2 million people need per day?
为了维持生命，每人每天大约需要2.5升水，200万人每天大约需要多少升水．
<gadget id="calculator">200 * 10_000</gadget>
<output>2_000_000</output>

<gadget id="calculator">2.5 * 2_000_000</gadget>
<output>5_000_000</output>

<result>5_000_000</result>