bjr
Calculer A= (-3)+(-2)-(-6) = -3 - 2 + 6 = -5 + 6 = 1
B= (-7) -(-1)+(-6)+(-3) = -7 + 1 - 6 - 3 = -7 - 6 - 3 + 1 = -16 + 1 = - 15
C=1/3-4/7 = 1x7/3x7 - 4x3/7x3 = 7/21 - 12/21 = -5/21
D= 1/7x(9/4+1/2) = 1/7 x (9/4 + 2/4) = 1/7 x (11/4) = 1x11/7x4 = 11/28
