Réponse:
Bonsoir
Explications étape par étape:
A = 2/5 + 5/6
= 4/6 + 5/6
= 9÷3/6÷3
A = 3/2
B = 4/5 - 1/5 × 9/2
= 4/5 - 9/10
= 8/10 - 9/10
B = -1/10
C = 1 + 12/8
= 8/8 + 12/8
= 20÷4/8÷4
C = 5/2
D = 7/9 × 6/21
= 42÷21/189÷21
D = 2/9
