A glass of milk, Xiao Ming drank (2/5) of this glass of milk for the first time, and drank (1/6) of this glass of milk for the second time, what fraction of this glass of milk is left?
一杯牛奶，小明第一次喝了这杯牛奶的(2/5)，第二次喝了这杯牛奶的(1/6)，还剩这杯牛奶的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (2/5) - (1/6)</gadget>
<output>13/30 = around 0.433333</output>

<result>13/30 = around 0.433333</result>