In 2:15, if 4 is added to the former term, how much should the latter term be multiplied to keep the ratio constant
在2：15中，如果前项加上4，要使比值不变，后项应乘多少
<gadget id="calculator">2 + 4</gadget>
<output>6</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<result>3</result>