(3/4): The former term of 6 is multiplied by 4. To keep the ratio unchanged, how much should be added to the latter term.
(3/4)：6的前项乘4，要使比值不变，后项应该加上多少．
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">24 - 6</gadget>
<output>18</output>

<result>18</result>