A factory originally used 468 tons of water per month. After carrying out water saving and water saving activities, the original year's water consumption can now be used for an extra month. How many tons of water can be saved on average per month?
一家工厂原来每月用水468吨．开展节水用水活动后，原来一年的用水量现在可以多用1个月，平均每月节水多少吨？
<gadget id="calculator">12 + 1</gadget>
<output>13</output>

<gadget id="calculator">12 / 13</gadget>
<output>12/13 = around 0.923077</output>

<gadget id="calculator">468 * (12/13)</gadget>
<output>432</output>

<gadget id="calculator">468 - 432</gadget>
<output>36</output>

<result>36</result>