60 : 30 = 2
600 : 30 = 20
(657 - 337) : 80 = 320 : 80 = 4
(456 + 44) : 10 = 500 : 10 = 50
(5 + 4) • 7 = 9 • 7 = 63
(96 + 4) • 8 = 100 • 8 = 800