Bonjour,
A= 11/2 + 4/3 -5/2 +3/4 -1/3 =
11/2 -5/2 + 4/3 -1/3 +3/4 =
6/2 +3/3 +3/4=
6/2 + 1 +3/4=
12/4 +3/4 + 1 =
15/4 + 1=
15/4 + 4/4 = 19/4