It is stipulated that A*B=(B+A)*B, (2*3)*5=how much.
规定A*B=(B+A)*B，(2*3)*5=多少．
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">15 * 5</gadget>
<output>75</output>

<result>75</result>