(1 1/2+2/3)х=(3/2+2/3)х=(9/6+4/6)х=13/6х=2 1/6х
(2 1/2+1 1/3)/1/6-2 3/7=(5/2+4/3)/1/6-17/7=(15/6+8/6)/1/6-17/7=23-17/7=20 4/7
(1 3/5+2 1/5)/1 9/10+(1 7/10-4/5)/3/7=38/10/19/10+9/10/3/7=2+63/30=4 1/10
1 8/9/(3 1/6-1 3/4)=17/9/(76/24-42/24)17/9/34/24=4/3=1 1/3