The school plans to invest 2 million yuan to build an activity building, but the actual investment is 1.8 million yuan. What percentage of the actual investment has been saved?
学校计划投资200万元建造活动大楼，实际投资180万元，实际投资节约了百分之几？
<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>