A = 9/7 + 6/7 même dénominateur on additionne juste 9+7 / 7
A = 9 + 6 / 7
A = 15/7
B = 17/5 - 8/5
B = 17 - 8 / 5
B = 9/5
C = - 7/13 + 5/13
C = - 7 + 5 / 13
C = - 2 / 13
D = 7/15 - 13/15
D = 7 - 13 / 15
D = - 6 / 15 on simplifie par 3 car 6=3x2 et 15 = 3x5
D = - 2 x 3 / 3 x 5
D = - 2 / 3
E = 3/4 + 4/7 on va mettre au même dénominateur 4x7 = 28
E = 3 x 7/4x7 + 4x4 /7x4
E = 21/28 + 16/28
E = 21 + 16 / 28
E = 37 / 28
F = 7/6 - 11 / 18
F = 7x3 / 6x3 - 11/18
F = 21/18 - 11/18
F = 10/18 simplification par 2
F = 2 x 5 / 2 x 9
F = 5/9
G = 13/5 + 1 1 c'est aussi 1/1
G = 13/5 + 1/1
G = 13/5 + 1x5/1x5
G = 13/5 + 5/5
G = 18/5
H = 3 + 3/5
H = 3/1 + 3/5
H= 3x5/1x5 + 3/5
H = 5/5 + 3/5
H =5+3/5
H = 8/5
I = 7/5 + 5/3 on met au même dénominateur 3 x 5 = 15
I = 7x 3/5x3 + 5x5 / 3x 5
I = 21/15 + 25 /15
I = 21 + 25 / 15
I = 46/15
J = 9/7 - 4/3
J = 9 x 3/7x3 - 4x7 /3x7
J = 27 / 21 - 28/21
J = 27 - 28 / 21
J = - 1/21
K = 7/5 + 5/7
K = 7x7/5x7 + 5x5/7x5
K = 49/35 + 25/35
K = 49 + 25/35
K = 74/35
L = 11/15 + 11/8
L = 11x8/15x8 + 11x15 / 8 x 15
L = 88 /120 + 165/120
L = 253/120
