5: Add 10 to the former term of 3, how much should be added to the latter term to keep the ratio constant
5：3的前项加上10，要使比值不变，后项应加上多少
<gadget id="calculator">9 - 5</gadget>
<output>4</output>

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

<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<result>6</result>