Add 5 to the former term of (5/6), to keep the ratio constant, how much should be added to the latter term
把(5/6)的前项加上5，要使比值不变，后项应该加多少
<gadget id="calculator">5 + 5</gadget>
<output>10</output>

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

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">12 - 6</gadget>
<output>6</output>

<result>6</result>