13-6+8= 14-9+6= 80-(12-7)= 90-(14-8)=
13-6+8=7+8=15 ; 14-9+6=5+6=11 ; 80-(12-7)=80-5=75
13-6=7+8=15 14-9=5+6=11 12-7=80-5=75 14-8=90-6=84
13-6+8=7+8=15 14-9+6=5+6=11 80-(12-7)=80-5=75 90-(14-8)=90-6=84