150/300+(30/300+80/300)
(21/90+16/90)+13/90
47/50-(15/50+2/50)= -2
6/20-(3/20-1/20)
210/300-(10/300+90/300)
(30/100+50/100)-70/100=80
150/300+(30/300+80/300)
(21/90+16/90)+13/90
47/50-(15/50+2/50)= -2
6/20-(3/20-1/20)
210/300-(10/300+90/300)
(30/100+50/100)-70/100=80