Bonjour ;
A = 6/7 - 4/7 x 5/2 = 6/7 - 10/7 = - 3/7 .
B = 2/3 - 3/2 x 4/9 + 1/2 = 2/3 - 2/3 + 1/2 = 1/2 .
C = (1/3 + 1/5) + (2/5 x 11/3) + (1/3 ÷ 5/11)
= (5 + 3)/15 + 22/15 + (1/3 x 11/5)
= 8/15 + 22/15 + 11/15 = 41/15 .
D = 5/6 + 7/8 x 1/3 - 1/16 ÷ 3/8
= 5/6 + 7/24 - 1/16 x 8/3 = 5/6 + 7/24 - 1/6
= 4/6 + 7/24 = 16/24 + 7/24 =23/16 .
E = (1/2 + 4/3)/(1/3 - 2) = (3 + 8)/6) / (1/3 - 6/3)
= (11/6) / (- 5/3) = 11/6 x 3/(- 5) = - 11/10 .