a★b=a*b+ab then 2★3=how much.
a★b=a*b+a-b那么2★3=多少．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">2 - 3</gadget>
<output>-1</output>

<gadget id="calculator">6 + (-1)</gadget>
<output>5</output>

<result>5</result>