5-2,8/9+4;/7; 2,2/7+3,1;/4-0,7

1/4+7/10-1/5=5/20+14/20-4/20=15/20=3/48/10-3/10-2/5=8/10-3/10-4/10=1/10=0.14/5-1/3+6/10=24/30-10/30+18/30=32/307/9+4/10-6/10=70/90+36/90-54/90=52/90