For a fraction, the sum of the numerator and the denominator is 45, which is (7/8) after division. What is the fraction?
一个分数，分子和分母的和是45，约分后是(7/8)，这个分数是多少．
<gadget id="calculator">8 + 7</gadget>
<output>15</output>

<gadget id="calculator">7 / 15</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">45 * (7/15)</gadget>
<output>21</output>

<gadget id="calculator">21 / 28</gadget>
<output>3/4 = around 0.75</output>

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