For a fraction, the sum of the numerator and denominator is 28. If 2 is subtracted from the numerator, the fraction equals 1. What is the original fraction?
一个分数，分子和分母的和是28．如果分子减去2，这个分数就等于1，原分数是多少．
<gadget id="calculator">2 + 28</gadget>
<output>30</output>

<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">28 - 15</gadget>
<output>13</output>

<gadget id="calculator">30 / 2 / 13</gadget>
<output>15/13 = around 1.153846</output>

<result>15/13 = around 1.153846</result>