Réponse:
39/12 = 13x3 /4x3 = 13/4
55/40 = 11x5 / 8x5 = 11/8
400/300 = 4x100 /3x100 = 4/3
45/27 = 5x9 /3x9 = 5/3
Bonne soirée !
