Réponse :
Explications étape par étape
Bjr,
A= 4/7 -1/7 +1/7 = 4/7
B= 19/4 -(1/2 -3/8 +2/8 )= 19/4 -1/2 +3/8 -2/8 =
36/8 -4/8 +1/8= 33/8
C=
7/12 -1/6 = 7/12 -2/12 = 5/12
3/4 -1/3 = 9/12-4/12 = 5/12
5/12 -5/12 = 0
D=
0,8 = 80/100
97/100 -80/10 = 17/100
3/10 = 30/100
30/100 - 17/100 =13/100
☺