"It's a little bit of a small thing, and it's a big thing to save." Every time Congcong brushes his teeth, he pours water for 30 seconds without interruption, and uses about 6 liters of water. Mingming uses cups to catch water to brush his teeth. He needs 3 cups of water, and each cup needs 0.2 liters. If he brushes his teeth twice a day, then Mingming is better than Congcong. How many liters of water is saved annually?
"点滴事小，节约事大"．聪聪每次刷牙时，不间断的放水30秒，用水约6升，明明则用杯子接水刷牙，需要3杯水，每杯需要0.2升，如果一天刷牙2次，那么明明比聪聪一年大约节约用水多少升？
<gadget id="calculator">6 * 2 * 365</gadget>
<output>4_380</output>

<gadget id="calculator">0.2 * 3 * 2 * 365</gadget>
<output>438</output>

<gadget id="calculator">4_380 - 438</gadget>
<output>3_942</output>

<result>3_942</result>