Add 18 to the former item of 6:11, to keep the ratio unchanged, how much should the latter item be increased.
把6：11的前项加上18，要使比值不变，后项应增加多少．
<gadget id="calculator">11 * 4</gadget>
<output>44</output>

<gadget id="calculator">44 - 11</gadget>
<output>33</output>

<result>33</result>