bonsoir ,
A = ( 11/3 - 7 ) ( 25/6 )
A = ( 11/3 - 21/3) * 25/6
A = - 10 /3 * 25/6 = - 250 /18 = - 125/9
B = ( 1/3 - 1/2) : 2/5
B = ( 2/6 - 3/6) : 2/5
B = - 1/6 x 5/2 = - 5/12
C = 5/4 - 9/13 * 65/81 + 11/36
C = 5/4 - 65/117 + 11/36
c = 5/4 - 5/9 + 11/36
c = 45/36 - 20/36 + 11/36 = 36/36 = 1