In 2:5, if 12 is added to the former term, how much should be added to the latter term so that the ratio remains unchanged.
在2：5中，如果前项加上12，后项要加上多少，比值才不变．
<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">5 * 7</gadget>
<output>35</output>

<gadget id="calculator">35 - 5</gadget>
<output>30</output>

<result>30</result>