After adding 20 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20后，要使分数的大小不变，分母应加上多少
<gadget id="calculator">24 / 4</gadget>
<output>6</output>

<gadget id="calculator">7 * 6</gadget>
<output>42</output>

<gadget id="calculator">42 - 7</gadget>
<output>35</output>

<result>35</result>