A fraction, if the denominator is subtracted by 1, the simplified result is (1/3), if the numerator is added by 4, the simplified result is (1/2), what is the fraction.
一个分数，若分母减1，化简后得(1/3)，若分子加4，化简后得(1/2)，这个分数是多少．
<gadget id="calculator">3 * 7</gadget>
<output>21</output>

<gadget id="calculator">21 + 1</gadget>
<output>22</output>

<gadget id="calculator">7 / 22</gadget>
<output>7/22 = around 0.318182</output>

<result>7/22 = around 0.318182</result>