(1
8/9:17/9)+2×(3 1/2-13×7 1/2) =
=(17/9:17/9)+2×(7/2-13×15/2) =
=1+2×(7/2-195/2) =
=1+2×(-188/2) =
=1-188 =-187
(13/5-2 1/3×6/7)×1 3/7+1/7=
= (13/5-7/3×6/7)×10/7+1/7=
= (13/5-2)×10/7+1/7=
= 3/5×10/7+1/7=
= 6/7+1/7=7/7=1
[1/2+3×(8 1/4×10/11-1/2)]×2/43+1 =
= [1/2+3×(33/4×10/11-1/2)]×2/43+1 =
= [1/2+3×(15/2-1/2)]×2/43+1 =
=(1/2+3×7)×2/43+1 =
=(1/2+21)×2/43+1 =
=43/2×2/43+1 =1