on n'a pas les méthodes de l'ex 1. mais bon

24/6 de 5 = 24/6 x 5 soit 24x5 / 6 = 4x6x5/6 = 4x5 = 20

20/3 de 6 = 20/3 x 6 = 20x6/3 = 20x3x2/3 = 20x2 = 40

2/8 de 36 = 2/8 x 36 = 2x36/8 = 2x4x9/2x4 = 9