In 2:3, if 4 is added to the former term, if the ratio remains the same, how much should be added to the latter term
在2：3中，如果前项加上4，要是比值不变，后项应加上多少
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">9 - 3</gadget>
<output>6</output>

<result>6</result>