For a fraction, its numerator is reduced to (2/5) after being reduced to the original (1/2), what is the fraction ((())/(())).
一个分数，把它的分子缩小为原来的(1/2)后是(2/5)，这个分数是((())/(()))多少．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

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