Read a book, read (1/5) of the whole book every day, how much of the whole book you read in 4 days.
看一本书，每天看全书的(1/5)，4天看了全书的多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 4</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>