A fraction is divided into (5/7), and the sum of the numerator and denominator of the original fraction is 72, so what is the original fraction?
一个分数约分后是(5/7)，原分数的分子、分母之和是72，那么原分数是多少？
<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">72 * (7/12)</gadget>
<output>42</output>

<gadget id="calculator">(5/12) / 42</gadget>
<output>5/504 = around 0.009921</output>

<gadget id="calculator">72 * (5/504)</gadget>
<output>5/7 = around 0.714286</output>

<result>5/7 = around 0.714286</result>