A factory used 308 tons of steel last month, saving 42 tons compared to the original plan. What percentage was the saving?
某厂上月用钢材308吨，比原计划节约了42吨，节约了百分之几？
<gadget id="calculator">308 + 42</gadget>
<output>350</output>

<gadget id="calculator">42 / 350</gadget>
<output>3/25 = around 0.12</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(3/25) * 1</gadget>
<output>3/25 = around 0.12</output>

<result>3/25 = around 0.12</result>