What is the simplest true fraction whose product of numerator and denominator is 63?
一个最简真分数，它的分子与分母的积是63，这个最简真分数是多少．
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<result>7/9 = around 0.777778</result>