a)(5/6 +0,25)×1/2+11/6×0,25 =
=(5/6 +1/4)×1/2+11/6×1/4 =
=(10+3)/12×1/2+11/24 =
=13/24+11/24 =
=24/24=1
b)[1/6+0,(7)]×3/17+0,8(3)=
=[1/6+7/9]×3/17+(83-8)/90=
=(3+14)/18×3/17+75/90=
=17/6×1/17+5/6=
=1/6+5/6=
=6/1=1
c)[0,1(6)+0,375]×6/13+0,75=
=[(16-1)/90+375/1000]×6/13+75/100=
=(15/90+3/8)×6/13+3/4=
=(1/6+3/8)×6/13+3/4=
=(4+9)/24×6/13+3/4=
=13/24×6/13+3/4=
=6/24+3/4=
=1/4+3/4=
=4/4=1
d)[0,41(6)-0,0(5)]×6/11+0,8(3)
=
=[(416-41)/900-5/90]×6/11+(83-8)/90
=
=(375/900-1/18)×6/11+75/90
=
=(5/12-1/18)×6/11+5/6
=
=(15-2)/36×6/11+5/6
=
=13/6×1/11+5/6
=
=13/66+5/6
=
=(13+55)/66=
=68/66=
=34/33