A fraction is (3/4) after simplification. If you subtract 2 from the numerator and 4 from the denominator of the original fraction, you will get a new fraction. This fraction is (5/6) after simplification. What is the original fraction?
一个分数化简后是(3/4)，如果将原分数的分子减去2，分母减去4，就得到一个新分数，这个分数化简后是(5/6)，原分数是多少．
<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">12 / 16</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>