steelmaking plant produces 180 tons of steel per month, 30 tons more than planned, by what percentage?
某炼钢厂每月炼钢180吨，超过计划30吨，超过百分之几？
<gadget id="calculator">180 - 30</gadget>
<output>150</output>

<gadget id="calculator">30 / 150</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>