When a=2.5, b=3.3, what is the value of the formula (ba)·a
当a=2.5，b=3.3时，式子(b-a)•a的值是多少
<gadget id="calculator">3.3 - 2.5</gadget>
<output>0.8</output>

<gadget id="calculator">0.8 * 2.5</gadget>
<output>2</output>

<result>2</result>