Use "•" to represent a new operation symbol, known 2•3=2+3+4=9, 4•2=4+5=9, 3•4=3+4+5+6=18, Then 7 • 6 = how much.
用"•"表示一种新的运算符号，已知2•3=2+3+4=9，4•2=4+5=9，3•4=3+4+5+6=18，那么7•6=多少．
<gadget id="calculator">7 + 8 + 9 + 10 + 11 + 12</gadget>
<output>57</output>

<result>57</result>