fraction in the simplest form, if the numerator is added by 1, the fraction will be (2/3). If you subtract 1 from the numerator, you get (1/2) after dividing. What is the simplest fraction.
一个最简分数，如果分子加1，约分后的(2/3)．如果分子减去1，约分后得(1/2)．这个最简分数是多少．
<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<result>7/12 = around 0.583333</result>