If the numerator of (3/7) is multiplied by 5, how many times should the denominator be increased to keep the size of the fraction constant.
(3/7)的分子乘以5，要使分数的大小不变，分母要增加多少倍．
<gadget id="calculator">7 * 5</gadget>
<output>35</output>

<gadget id="calculator">35 - 7</gadget>
<output>28</output>

<gadget id="calculator">28 / 7</gadget>
<output>4</output>

<result>4</result>