Calculation: 3*((2/15)+(1/12))-(2/5).
计算：3*((2/15)+(1/12))-(2/5)．
<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(2/15) + (1/12)</gadget>
<output>13/60 = around 0.216667</output>

<gadget id="calculator">3 * (13/60)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(13/20) - (2/5)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>