There is a simple fraction, if you add 2 to its numerator, it can be reduced to (3/10), if you subtract 2 from its denominator, it can be reduced to (1/4), then what is the original fraction.
有一个简单分数，若给它的分子加上2，可约简为(3/10)，若给它的分母减去2，可约简为(1/4)，那么原来这个分数是多少．
<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">4 * 7</gadget>
<output>28</output>

<gadget id="calculator">28 + 2</gadget>
<output>30</output>

<gadget id="calculator">7 / 30</gadget>
<output>7/30 = around 0.233333</output>

<result>7/30 = around 0.233333</result>