2/3+(1/4+3/8)= 2/3+(2/8+3/8)= 2/3+5/8= 16/24+15/24= 31/249/13-(7/10-1/2)= 9/13-(7/10-5/10)= 9/13-1/5=45/65-13/65=32/652/5+(5/6-2/3)=2/5+(5/6-4/6)=2/5+1/6=12/30+5/30=17/30