The factory plans to use 48 tons of coal in the first quarter (3 months), but the actual average monthly coal consumption is 12 tons. How many tons of coal is actually saved each month compared with the original plan?
工厂计划第一季度(3个月)用煤48吨，实际平均每个月用煤12吨．实际每个月比原计划节约用煤几吨？
<gadget id="calculator">48 / 3</gadget>
<output>16</output>

<gadget id="calculator">16 - 12</gadget>
<output>4</output>

<result>4</result>