Câu 1:
a)13/4+27/8:3/2=13/4+9/4=22/4
b)1/2.-3/2+5/2.3/2=-1/2.3/2+5/2.3/2=3/2.(-1/2+5/2)=3/2.2=3
c)Không nhìn rõ
d)1/99.97-1/97.95-1/95.93-1/93.91-......-1/5.3-1/3.1
=1/99.97-(1/97.95+1/95.93+1/93.91+......+1/5.3+1/3.1)
=1/99.97-1/2(1/95-1/97+1/93-1/95+1/91-1/93+......+1/3-1/5+1-1/3)
=1/99.97-1/2(1-1/97)
=1/99.97-1/2.96/97
=1/99.97-48/97
=1/99.97-48.99/97.99
=-4751/99.97