A fraction is divided into (3/5), if the sum of the numerator and denominator of the original fraction is 72, what is the original fraction.
一个分数约分之后为(3/5)，如果原分数的分子、分母之和为72，原分数多少．
<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">72 * (5/8)</gadget>
<output>45</output>

<gadget id="calculator">(3/8) / 45</gadget>
<output>1/120 = around 0.008333</output>

<gadget id="calculator">72 * (1/120)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>