Add 6 to the former term of 8:15, to keep the ratio constant, how much should be added to the latter term
给8：15的前项加上6，要使比值不变，后项应该加上多少
<gadget id="calculator">8 + 6</gadget>
<output>14</output>

<gadget id="calculator">14 / 8</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">15 * (7/4)</gadget>
<output>105/4 = around 26.25</output>

<gadget id="calculator">(105/4) - 15</gadget>
<output>45/4 = around 11.25</output>

<result>45/4 = around 11.25</result>