There is a new operator "*", which makes the following formulas true: 5*3=7, 3*5=1, 8*4=12, 3*4=2, then 7*2=how much.
有一个新算符"*"，使下列算式成立：5*3=7，3*5=1，8*4=12，3*4=2，那么7*2=多少．
<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<gadget id="calculator">14 - 2</gadget>
<output>12</output>

<result>12</result>