Use * to represent an operation symbol, if x*y=(1/(xy))+(1/((x+1)(y+A))), and 2*1=(7/12), find The value of 3*1.
用*表示一种运算符号，如果x*y=(1/(xy))+(1/((x+1)(y+A)))，且2*1=(7/12)，求3*1的值．
<gadget id="calculator">3 * 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">1 / 16</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">(1/3) + (1/16)</gadget>
<output>19/48 = around 0.395833</output>

<result>19/48 = around 0.395833</result>