30.6 minus the difference between 12.1 and 8.7, what is the difference?
30.6减去12.1与8.7的差，差是多少？
<gadget id="calculator">12.1 - 8.7</gadget>
<output>3.4</output>

<gadget id="calculator">30.6 - 3.4</gadget>
<output>27.2</output>

<result>27.2</result>