Prescribed operation: a☆b=5a-2b, find ((3/5)☆(4/3))☆(2/3).
规定运算：a☆b=5a-2b，求((3/5)☆(4/3))☆(2/3)．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">5 * (1/3)</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">2 * (2/3)</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">(5/3) - (4/3)</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>