slt exo de math des fraction de niveau 4eme il fait faire tous les calculs pas que les reponse svp merci d'avance 20pts

1)
A = 1/9 + 1/6
A = 1 x 2 / 9 x 2 + 1 x 3 / 6 x 3
A = 2/18 + 3/18
A = 5/18

B = 1/12 + 1/30
B = 1 x 5 / 12 x 5 + 1 x 2 / 30 x 2
B = 5/60 + 2/60
B = 7/60

C = 3 + 5/6
C = 3 x 6 / 1 x 6 + 5/6
C = 18/6 + 5/6
C = 23/6

2)
D = 11/12 + 7/4
D = 11/12 + 7 x 3 / 4 x 3
D = 11/12 + 21/12
D = 32/12
D = 4 x 8 / 4  3
D = 8/3

E = 5/21 + 1/14
E = 5 x 2 / 21 x 2 + 1 x 3 / 14 x 3
E = 6/42 + 3/42
E = 9/42
E = 3 x 3 / 3 x 14
E = 3/14

3)
A = 5/18 + - 5/8
A = 5/18 - 5/8
A = 5 x 4 / 18 x 4 - 5 x 9 / 8 x 9
A = 20/72 - 45/72
A = - 25/72

B = 7/12 - 5/9
B = 7 x 3 / 12 x 3 - 5 x 4 / 9 x 4
B= 21/36 - 20/36
B = 1/36

C = 2/15 + - 6/25
C = 2/15 - 6/25
C = 2 x 5 / 15 x 5 - 6 x 3 / 25 x 3
C = 10/75 - 18/75
C = - 8/75

4)
D = 1 - 7/5
D = 1 x 5 / 1 x 5 - 7/5
D = 5/5 - 7/5
D = - 2/5

E = 11/45 + 7/30
E = 11 x 2 / 45 x 2 + 7 x 3 / 30 x 3
E = 22/90 + 21/90
E = 41/90

5)
A = 14/15 x 5/7
A = 70/105
A = 35 x 2 / 35 x 3
A = 2/3

B = 7/9 x 27/25 x 15/14
B = 189/225 x 15/14
B = 2835/3150
B = 315 x 9 / 315 x 10
B = 9/10