The sum of the numerator and the denominator of a fraction is 72, and the sum of the fraction is (2/7). What is the original fraction?
一个分数分子与分母的和是72，约分后是(2/7)，这个原分数是多少．
<gadget id="calculator">2 + 7</gadget>
<output>9</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">72 * (7/9)</gadget>
<output>56</output>

<gadget id="calculator">(2/9) / 56</gadget>
<output>1/252 = around 0.003968</output>

<gadget id="calculator">72 * (1/252)</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>