A project, complete its (1/7) every day, how much is the project completed in 4 days.
一项工程，每天完成它的(1/7)，4天完成这项工程的多少．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/7) * 4</gadget>
<output>4/7 = around 0.571429</output>

<result>4/7 = around 0.571429</result>