In 2:5, add 8 to the former term of the ratio, how much should be added to the latter term of the ratio
在2：5中，比的前项加8，比的后项要加上多少
<gadget id="calculator">2 + 8</gadget>
<output>10</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">25 - 5</gadget>
<output>20</output>

<result>20</result>