If a fraction is multiplied by (14/15) or (7/10), the result will be an integer. What is the smallest fraction.
一个分数去乘(14/15)或乘(7/10)，结果都得整数，这个分数最小是多少．
<gadget id="calculator">30 / 7</gadget>
<output>30/7 = around 4.285714</output>

<result>30/7 = around 4.285714</result>