Réponse :
Bjr,
A = (1/4-3/4) : 5/2
A = -2/4 : 5/2
A = -1/2 * 2/5
A = -2/10
A = -1/5
B = (2+1/3) * (1/4 + 1/6)
B = (6/6 + 1/3) * (1*3/4*3 + 1*2/6*2)
B = 7/3 * (3/12+2/12)
B = 7/3 * 5/12
B = 7*5/3*12
B = 35/36
C = 8/7 - 5/7 * 3/5
C = 8/7 - 5*3/7*5
C = 8/7 - 15/35
C = 8/7 - 3/7
C = 5/7
J'espère avoir pu vous aider
