Expansion of a project, investment of 400,000 yuan, saving 100,000 yuan compared to the original plan, saving a few percent?
扩建一项工程，投资40万元，比原计划节约了10万元，节约了百分之几？
<gadget id="calculator">40 + 10</gadget>
<output>50</output>

<gadget id="calculator">10 / 50</gadget>
<output>1/5 = around 0.2</output>

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