Xiao Ming has a bad habit of brushing his teeth. He does not turn off the faucet when brushing his teeth. According to statistics, a faucet loses about 500 grams of water every 10 seconds. Calculated by brushing his teeth for 180 seconds a day, how many kilograms of water does Xiao Ming lose by brushing his teeth a day?
小明刷牙有坏习惯，刷牙时不关闭水龙头，据统计一个水龙头每10秒流失的水约是500克，按每天刷牙180秒计算，小明一天刷牙流失的水大约是多少千克？
<gadget id="calculator">180 / 10</gadget>
<output>18</output>

<gadget id="calculator">500 / 1_000</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">18 * (1/2)</gadget>
<output>9</output>

<result>9</result>