After adding 28 to the numerator of (4/7), how much should be added to the denominator to keep the size of the fraction unchanged.
(4/7)的分子加上28以后，要使分数的大小不变，分母应加多少．
<gadget id="calculator">4 + 28</gadget>
<output>32</output>

<gadget id="calculator">32 / 4</gadget>
<output>8</output>

<gadget id="calculator">7 * 8</gadget>
<output>56</output>

<gadget id="calculator">56 - 7</gadget>
<output>49</output>

<result>49</result>