(6 8/11*4/5)*1 1/4
1)6 8/11*4/5=74/11*4/5=296/55=5 21/55
2)5 21/55*1 1/4=296/55*5/4=74/11*1/1=74/11*1=74/11=6 8/11
2 5/6*(17,8*6/17)
1)17,8*6/17=17 8/10*6/17=178/10*6/17=1068/170=6 48/170=6 24/85
2 5/6* 6 24/85=17/6*534/85=1/3*267/5=267/15=17 12/15=17 4/5