bonsoir
A = 2/3 - 56/63 = 42/63 - 56/63 = - 14/63
B = ( 9/12 - 10/12 ) x 3 /2 = - 1/12 x 3/2 = - 3 /24 = - 1 /8
C = 11 : ( 4/6 - 15/6 ) = 11 : - 11 /6 = 11 x - 6 /11 = - 66 /11 = - 6
D = 3/7 - 15/7 : 5/24 = 3/7 - 15/7 x 24/5 = 3 /7 - 360 / 35 = 3/7 - 72 / 7 = - 69/7
continue, tu as assez d'exemples
