For a fraction, the sum of the numerator and denominator is 45. If 3 is subtracted from both the numerator and denominator of this number, the resulting fraction is (6/7), what is the original fraction
一个分数，分子、分母的和是45．如果把这个数的分子、分母都减去3，所得的分数是(6/7)，原来的分数是多少
<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">(6/7) * 45</gadget>
<output>270/7 = around 38.571429</output>

<gadget id="calculator">(6/7) * 3</gadget>
<output>18/7 = around 2.571429</output>

<gadget id="calculator">(270/7) - (18/7)</gadget>
<output>36</output>

<gadget id="calculator">3 + 36</gadget>
<output>39</output>

<gadget id="calculator">1 + (6/7)</gadget>
<output>13/7 = around 1.857143</output>

<gadget id="calculator">39 / (13/7)</gadget>
<output>21</output>

<gadget id="calculator">45 - 21</gadget>
<output>24</output>

<gadget id="calculator">39 / (13/7) / 24</gadget>
<output>7/8 = around 0.875</output>

<result>7/8 = around 0.875</result>