Suppose x, y, A are rational numbers, define x*y=((Axy)/(4x+5y)), and 1*2=1, try to find the value of 2*3.
设x、y，A都是有理数，定义x*y=((Axy)/(4x+5y))，并且1*2=1，试求2*3之值．
<gadget id="calculator">7 * 2 * 3</gadget>
<output>42</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

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

<gadget id="calculator">8 + 15</gadget>
<output>23</output>

<gadget id="calculator">42 / 23</gadget>
<output>42/23 = around 1.826087</output>

<result>42/23 = around 1.826087</result>