The school planned to invest 2 million yuan in building a comprehensive building, but actually only spent 1.8 million yuan. How much was the savings?
学校建一幢综合楼，原计划投资200万元，实际只用了180万元，节约了百分之几？
<gadget id="calculator">200 - 180</gadget>
<output>20</output>

<gadget id="calculator">20 / 200</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>