If a&b=a*b+ab, then 2&3=how much.
如果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>