Réponse :
1er tableau :
2/5 x 9/10 = 18/50 = 9/25
3/10 x 5/2 = 15/20 = 3/4
9/25 x 3/4 = 27/100
2/5 x 3/10 = 6/50 = 3/25
9/10 x 5/2 = 45/20 = 9/4
2e tableau :
7/6 : 2/3 = 7/6 x 3/2 = 21/12
21/12 x 3 = 63/12 = 21/4
7/4 : 21/4 = 7/4 x 4/21 = 1/3
7/4 : 7/6 = 7/4 x 6/7 = 3/2
3/2 : 3 = 3/2 x 1/3 = 1/2
1/3 : 2/3 = 1/3 x 3/2 1/2