For a fraction, add 1 to its numerator to get (1/4); subtract 1 to its denominator to get (1/5). How much is this score?
一个分数，给它的分子加1，后得(1/4)；给它的分母减1，得(1/5)．这个分数多少．
<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<gadget id="calculator">12 + 4</gadget>
<output>16</output>

<gadget id="calculator">3 / 16</gadget>
<output>3/16 = around 0.1875</output>

<result>3/16 = around 0.1875</result>