Multiply a fraction by (5/28), (15/56), and (20/21) respectively, and the resulting quotients are all integers. What is the smallest fraction?
用(5/28)、(15/56)、(20/21)分别去乘某一个分数，所得的商都是整数，这个分数最小是多少．
<gadget id="calculator">2 * 3 * 4 * 7</gadget>
<output>168</output>

<gadget id="calculator">168 / 5</gadget>
<output>168/5 = around 33.6</output>

<result>168/5 = around 33.6</result>