The sum of the numerator and denominator of a fraction is 108, and (4/5) is obtained after the division. What is the original fraction?
一个分数的分子和分母之和是108，约分后得(4/5)，求原来的分数是多少？
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">108 * (5/9)</gadget>
<output>60</output>

<gadget id="calculator">(4/9) / 60</gadget>
<output>1/135 = around 0.007407</output>

<gadget id="calculator">108 * (1/135)</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>