For a project, the ratio of the finished project to this project is 3:5, how much of this project is left
一项工程，已经完成的与这项工程的比是3：5，还剩这项工程的多少
<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>