(2,7+1 1/3-1 4/5)*1 53/67=(2 7/10+1 1/3-1 4/5)*1 53/67=(2 21/30+1 10/30-1 24/30)*1 53/67=
(4 1/30-1 10/30)*1 53/67=2 21/30*1 53/67=2 7/10*1 53/67=27/10*120/67=324/67=4 56/67
(2,7+1 1/3-1 4/5)*1 53/67=(2 7/10+1 1/3-1 4/5)*1 53/67=(2 21/30+1 10/30-1 24/30)*1 53/67=
(4 1/30-1 10/30)*1 53/67=2 21/30*1 53/67=2 7/10*1 53/67=27/10*120/67=324/67=4 56/67