The number A is (3/5) the average of the two numbers B and C, and the number A is the average of the three numbers A, B and C.
数A是数B和C两个数的平均数的(3/5)，数A是数A、B和C三个数平均数的多少．
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">10 + 3</gadget>
<output>13</output>

<gadget id="calculator">13 / 3</gadget>
<output>13/3 = around 4.333333</output>

<gadget id="calculator">3 / (13/3)</gadget>
<output>9/13 = around 0.692308</output>

<result>9/13 = around 0.692308</result>