The sum of the numerator and the denominator of a fraction is 42. After dividing it, we get (1/5). What is the original fraction?
一个分数的分子与分母的和是42，约分后得(1/5)，原来这个分数是多少．
<gadget id="calculator">1 + 5</gadget>
<output>6</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">42 * (5/6)</gadget>
<output>35</output>

<gadget id="calculator">(1/6) / 35</gadget>
<output>1/210 = around 0.004762</output>

<gadget id="calculator">42 * (1/210)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>