计算
2^100*(-1/2)^101
=-2^100*(1/2)^101
=-(2x1/2)^100x1/2
=-1x1/2
=-1/2
(2/5)^2013*(-2又1/2)^2014
=(2/5)^2013*(2又1/2)^2014
=(2/5x2又1/2)^2013*2又1/2
=1x2又1/2
=2又1/2