(1 1/5+2 3/10):1/2+(6 3/4-2 2/3):1 1/6=
=(1 2/10+2 3/10):1/2+(6 9/12-2 8/12):1 1/6=
=3 5/10:1/2+4 1/12:1 1/6=
=35/10*2+49/12*6/7=
=35/5+7/2=7+7/2=7 7/2=10 1/2
(1 1/5+2 3/10):1/2+(6 3/4-2 2/3):1 1/6=
=(1 2/10+2 3/10):1/2+(6 9/12-2 8/12):1 1/6=
=3 5/10:1/2+4 1/12:1 1/6=
=35/10*2+49/12*6/7=
=35/5+7/2=7+7/2=7 7/2=10 1/2