Zhangzhuang Brick and Tile Factory planned to use 400 tons of coal in the first half of the year, but actually used 388 tons of coal. What percentage was saved?
张庄砖瓦厂上半年计划用煤400吨，实际用煤388吨，节约了百分之几？
<gadget id="calculator">400 - 388</gadget>
<output>12</output>

<gadget id="calculator">12 / 400</gadget>
<output>3/100 = around 0.03</output>

<result>3/100 = around 0.03</result>