A food processing factory used 640 tons of water in September. After installing the water-saving faucet in October, the planned water consumption is September (9/10), but the actual water consumption in October is more than the original plan (1/12). How many tons did the actual water use save in October compared with the original plan?
某食品加工厂九月份用水640吨．十月份安装节水龙头之后，计划用水是九月份的(9/10)，而十月份实际用水比原计划还节约了(1/12)．十月份实际用水比原计划节约多少吨？
<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">640 * (9/10) * (1/12)</gadget>
<output>48</output>

<result>48</result>