6+6=12 9+3=12 7+7=14 8+0=8 9+9=18
6-6=0 9-3=6 7-7=0 8-0=-8 9-9=0
а) 23, 32, 27, 37, 72, 73
б) 22, 23, 27, 33, 32, 37, 72, 73, 77