1/2+1/6+1/12+1/20=(30+10+5+3)/60=48/60=0.8
1 4/9+2 5/6-2 3/4=13/9+17/6-11/4=(52+102-99)/36=55/36
55/36*6/11=5/6
1/2+1/6+1/12+1/20=(30+10+5+3)/60=48/60=0.8
1 4/9+2 5/6-2 3/4=13/9+17/6-11/4=(52+102-99)/36=55/36
55/36*6/11=5/6