"△" means a new operation, which is defined as follows: x△y=(x+y)-(xy). Find how much 7△6=.
"△"表示一种新的运算，它是这样定义的：x△y=(x+y)-(x-y)．求7△6=多少．
<gadget id="calculator">7 + 6</gadget>
<output>13</output>

<gadget id="calculator">7 - 6</gadget>
<output>1</output>

<gadget id="calculator">13 - 1</gadget>
<output>12</output>

<result>12</result>