五分之二除以二右五分之二减负一右三分之一的二次方乘以（负十六分之三
=2/5/12/5-(-4/3)²*（-3/16)
=2/5*5/12-16/9*(-3/16)
=1/6-(-1/3)
=1/6+2/6
=3/6
=1/2