When a=2.5, b=3.6, c=2.4, what is the value of bc-ac.
当a=2.5，b=3.6，c=2.4时，bc-ac的值是多少．
<gadget id="calculator">3.6 - 2.5</gadget>
<output>1.1</output>

<gadget id="calculator">2.4 * 1.1</gadget>
<output>2.64</output>

<result>2.64</result>