The sum of the numerator and denominator of a fraction is 50. If 5 is subtracted from both the numerator and the denominator, the fraction is (2/3). What is the original fraction?
一个分数分子与分母的和是50，如果分子和分母都减去5，约分后是(2/3)，原来那个分数是多少．
<gadget id="calculator">50 - 5 - 5</gadget>
<output>40</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">40 * (2/5)</gadget>
<output>16</output>

<gadget id="calculator">16 + 5</gadget>
<output>21</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">40 * (3/5)</gadget>
<output>24</output>

<gadget id="calculator">24 + 5</gadget>
<output>29</output>

<gadget id="calculator">21 / 29</gadget>
<output>21/29 = around 0.724138</output>

<result>21/29 = around 0.724138</result>