1.101*99-100又1/2*99又1/2

1.101*99-100又1/2*99又1/2

101*99-100又1/2*99又1/2
=(100+1)(100-1)-(100+1/2)(100-1/2)
=10000-1-(10000-1/4)
=-1+1/4
=-3/4